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81 Cards in this Set
- Front
- Back
Parallel lines
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two lines are this if they are coplanar and do not intersect
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Lines that do not intersect and are not coplanar are called
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skew lines
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Two planes that do not intersect are called
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Parallel planes
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transversal
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a line that intersects two or more coplanar lines at different points
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corresponding angles
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two angles are this if they occupy corresponding postions
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alternate exterior angles
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angles lying outside the two lines on opposite sides of the transversal
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two angles are __________ if they lie between the two lines on opposite sides of the transversal
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alternate interior angles
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Two angles are _____________ if they lie between the two lines on the same side of the transversal
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consecutive interior angles
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same side interior angles
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consecutive interior angles are sometimes called this
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________ ______ are coplaner and do not intersect
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Parallel Lines
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Skew Lines
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are noncoplaner and do not intersect.
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Parallel Postulate
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If there is a line and a point not on the line, then there is exactly one line through the point parallel to the given line
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If there is a line through the point perpendicular to the given line, then there is exactly one line through the point perpendicular to the given line
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Perpendicular Postulate
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If two lines are cut by a transversal so the corresponding angles are congruent then the lines are parallel
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Corresponding Angles Converse
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A transversal is a line that
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intersects two or more coplanar lines at different points
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Corresponding angles need to be ____________ in order for the lines to be parallel
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the same/congruent
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Consecutive interior angles are _____________ the lines are parallel
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supplementary
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Corresponding angles must be congruent for the lines to be ________
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parallel
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Alternate Interior Angles must be ___________ for the lines to be parallel
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congruent/ the same measure
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Vertical angles are
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congruent
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How do you determine if lines are parallel?
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1. If corresponding angles are congruent then the line are parallel
2. Alternate exterior angles are congruent 3. Alternate interior angles are congruent 4. consecutive exterior supplementary 5. Consecutive interior angles are supplentary |
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How do you tell if two lines cut by a transversal are parallel?
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One way is to look for corresponding angles to be congruent.
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flow proof
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uses arrows to show the flow of the logical argument. Each reason in a flow proof is written below the statement it justifies
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Alternate Interior Angles Theorem
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If two parallel lines are cut by a transversal then the pairs of alternate interior angles are congruent.
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Consecutive Interior Angles Theorem
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If two parallel lines are cut by a transversal then the pairs of consectuvie interior angles are supplementary
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Alternate Exterior Angles Theorem
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If two parallel lines are cut by a transversal then the pairs of alternate exterior angles are congruent
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Perpendicular Transversal
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If a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other
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Corresponding Angles Postulate
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If two parallel lines are cut by a transversal, then the pairs of corresponding angles are congruent.
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Corresponding Angles Converse
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If two lines are cut by a transversal so that corresponding angles are congruent, then the lines are parallel.
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Alternate Interior Angles Converse
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If two lines are cut by a transversal so the alternate interior angles are congruent, then the lines are parallel
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Consecutive Interior Angles Converse
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If two lines are cut by a transversal so that consecutive interior angles are supplementary, then the lines are parallel
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Alternate Exterior Angles Converse
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If two lines are cut by a transversal so that alternate exterior angles are congruent, then the lines are parallel
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When you are given the angles you are working backwards and using
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the converse thereom
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Consecutive Interior angles are _____________
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supplementary
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Theorem 3.11 If two lines are parallel to the same line, then they are parallel to
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each other
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Theorem 3:11 If two lines are _____________ to the same line, then they are parallel to each other.
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parallel
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Theorem 3:12
In a plane, if two lines are perpendicular to the same line, then they are parallel to ________ |
each other
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In a _______, if two lines are perpendicular to the same line, then they are parallel to each other.
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plane
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Slopes of Lines
Lines with positive slope |
rise
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Lines with negative slope
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fall
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Vertical lines are
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undefined or "no slope"
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Horizontal slope are lines with a slope of
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zero
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slope equation is y=
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mx+b
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Postulate 17: Slopes of Parallel lines.
In a coordinate plane, two ___________ lines are parallel if and only if they have the same slope. Any two vertical lines are ____________ |
nonvertical
parallel |
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In a coordinate plane, two nonvertical lines are perpendicular if and only if the product of their slopes is
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-1
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Vertical and horizontal lines
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are perpendicular
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A line's slope that rises from left to right is
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Positive
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A vertical line's slope is
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undefined
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A horizontal line's slope is
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zero
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A line that falls from left to right has a ______ slope
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negative
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You can use the _______ of two lines to tell whether the lines are parallel
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slopes
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What information is contained in the equation of a line written in slope-intercept form?
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The slope of the line and y-intercept
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If you know two points on line p and two points on line q how could you tell if p is parallel to q?
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Find the slope of each line using the slope formula. If the slopes are equal, the lines are parallel
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Write an equation of the line whose slope is 2 and whose y-intercept is -1
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y=2x-1
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Line m is perpendicular to line n. If line m has a positive slope, what kind of slope does line n have?
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a negative slope
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Write an equation of line that has slope 4 and y intercept 10.
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y=4x+10
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Line M is perpendicular to line n. If line M has a positive slope, what kind of slope does line n have?
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a negative slope
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In a coordinate plane, two nonvertical lines are ________if and only if the ____of their slopes is -1. Vertical and horizontal lines are perpendicular
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perpendicular,
product |
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The slope of one of two perpendicular lines is a/b. What is the slope of the other line?
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-b/a
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The ______ of two perpendicular lines are ____reciprocals of each other.
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slopes
negative |
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Linear Pairs
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add up to 180 degrees
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Corresponding angles
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are equal
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1.identifying the angles
2.Knowing their relationship 3. looking at the lines and setting up their equation 4.being able to tell if the lines are parallel |
Key things to know when approaching problems in Chapter 3
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Consectutive Interior Converse
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If two lines are cut by a transversal so that consecutive interior angles are supplementary, then the lines are parallel
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Vertical angles
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are congruent
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Corresponding Angles Converse
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If two lines are cut by a transversal so that corresponding angles are congruent, then the lines are parallel
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Alternate Interior Angles Converse
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If two lines are cut by a transversal so that alternate interior angles are congruen, then the lines are parallel
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Alternate Exterior Angles Converse
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If two lines are cut by a transversal so that alternate exterior angles are congruent, then the lines are parallel.
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Concept to know:
Parallel lines have equal |
slopes
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Write an equation of the line uses:
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y= mx + b
slope intercept form |
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Find the equation of a line whose y intercept is 3 and is parallel to y=x-8
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y=x + 3
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2 points are given
(-3,6) (0,3) Find the equation of the line? What do you need to do? |
1.Find the slope using the slope formula.
2. y=mx +b Plug in slope for m Plug in one of the points for y and x to get b Put it all together in the slope intercept form y=mx + b |
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The slopes of two _________ lines are negative reciprocals of each other.
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perpendicular
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In a coordinate plance, if two vertical lines are __________, then the product of their slopes is -1.
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perpendicular
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In a coordinate plane, if the product of the slopes of two lines is _______, then the lines are perpendicular.
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-1
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If you are trying to prove that two lines are _________ you use converse theorems.
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parallel
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If you are given the lines that are parallel and you are finding what angles are equal you uses
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theorem and postulates not theorem
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Corresponding angles are only equal if the two lines that form them are
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parallel
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If two angle measures are
2x-15 = x +30 they are |
congruent. We know that by the equal sign.
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Mrs West's Geometry test is
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Monday
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Complete the following to make a true statement;
In a plane, if two lines are ______ to the same line, then they are _______ to each other |
perpendicular, Parallel
OR parallel, parallel |