Geometry Exam Vocabulary Review

Front 1

Parallel Lines

Back 1

Two coplanar lines that don't intersect

Front 2

Skew Lines

Back 2

Two non-coplanar lines that don't intersect

Front 3

Transversal

Back 3

A line that intersects two or more coplanar lines at different points

Front 4

Corresponding Angles

Back 4

Angles with corresponding positions

Front 5

Alternate Interior Angles

Back 5

Angles that lie between two lines on the same side of the transversal

Front 6

Alternate Exterior Angles

Back 6

Lines that lie outside two lines on opposite sides of the transversal

Front 7

Consecutive Interior Angles

Back 7

Angles that lie between two lines on the same side of the transversal

Front 8

Paragraph Proof

Back 8

The Paragraph form of a proof

Front 9

Slope

Back 9

The ratio of rise over run between any two points

Front 10

Slope-intercept Form

Back 10

y = mx + b

Front 11

Standard Form

Back 11

Ax + By = C

Front 12

Distance from a point to a line

Back 12

The length of a perpendicular segment from the point to the line

Front 13

Triangle

Back 13

A polygon with three sides

Front 14

Scalene Triangle

Back 14

A triangle with no congruent sides

Front 15

Isosceles Triangle

Back 15

A triangle with at least two congruent sides

Front 16

Equilateral Triangle

Back 16

A triangle with three congruent sides

Front 17

Acute Triangle

Back 17

A triangle with three acute angles

Front 18

Right Triangle

Back 18

A triangle with one right angle

Front 19

Obtuse Triangle

Back 19

A triangle with one obtuse angle

Front 20

Equiangular Triangle

Back 20

A triangle with three congruent angles

Front 21

Interior Angles

Back 21

The original angles of a polygon when its sides are extended

Front 22

Exterior Angles

Back 22

The angles that form linear pairs with the interior angles

Front 23

Congruent Figures

Back 23

Figures in which all the parts of one figure correspond to the parts of the other

Front 24

Corresponding Parts

Back 24

The parts in congruent figures that correspond to parts in another figure

Front 25

Properties of Congruent Triangles

Back 25

The reflexive, symmetric, and transitive properties

Front 26

Transformation

Back 26

Functions that map points onto points

Front 27

Rigid Motion

Back 27

A transformation that preserves length and angle measure

Front 28

Leg of triangle

Back 28

The sides of a triangle that are adjacent to the right angle

Front 29

Hypotenuse of triangle

Back 29

The side opposite of the right angle

Front 30

Flow Proof

Back 30

A proof that uses arrows to show the flow of a logical argument

Front 31

Vertex Angles

Back 31

The angle formed by the legs of a triangle

Front 32

Base of Triangle

Back 32

The line formed between the legs of a triangle

Front 33

Base Angles

Back 33

The two angles adjacent to the base of the triangle

Front 34

Midsegment of a triangle

Back 34

A segment that connects the midpoints of two sides of a triangle

Front 35

Coordinate Proof

Back 35

A proof that involves placing geometric figures in a coordinate plane

Front 36

Perpendicular Bisector

Back 36

A segment, ray, line, or plane that is perpendicular to a segment at its midpoint

Front 37

Equidistant

Back 37

When a point is the same distance away from two figures, it is equidistant

Front 38

Concurrent Lines

Back 38

3 Lines, rays, or segments that intersect at the same spot

Front 39

Point of Concurrency

Back 39

Point of intersection for concurrent lines

Front 40

Circumcenter

Back 40

The point of concurrency of the three bisectors of a triangle

Front 41

Incenter

Back 41

The point of concurrency of the three angle bisectors of a triangle

Front 42

Median of a Triangle

Back 42

A segment from a vertex to the midpoint of the opposite side

Front 43

Centroid

Back 43

The point of concurrency inside the triangle

Front 44

Altitude of a Triangle

Back 44

The perpendicular segment from a vertex to the opposite side or to the line that contains the opposite side

Front 45

Orthocenter

Back 45

The point at which the lines containing the three altitudes of a triangle intersect

Front 46

Indirect Proof

Back 46

A proof in which you start by making the temporary assumption that the desired conclusion is false, then you show that it's false and prove the original statement by contradiction

Front 47

Corollary to a theorem

Back 47

A statement that can be easily proved using the theorem

Front 48

Point

Back 48

A point has no dimension, and is represented by a dot

Front 49

Line

Back 49

A line has one dimension and is represented by a line with two arrow-heads, it extends indefinitely

Front 50

Plane

Back 50

A plane has two dimensions and is represented by a shape that looks like a floor or wall, and it extends indefinitely

Front 51

Collinear Points

Back 51

Collinear points are points that lie on the same lime

Front 52

Coplanar Points

Back 52

Points that lie on the same plane

Front 53

Line Segment

Back 53

A line with definite endpoints

Front 54

Ray

Back 54

Any group of lines diverging from one point

Front 55

Intersection

Back 55

A set of points that figures have in common

Front 56

Postulate (axiom)

Back 56

A rule that is accepted without proof

Front 57

Coordinate

Back 57

The real number that corresponds to a point

Front 58

Distance

Back 58

The absolute value of the difference of the coordinates

Front 59

Congruent Segments

Back 59

Line segments that have the same length

Front 60

Midpoint

Back 60

The point that divides the segment into two congruent segments

Front 61

Segment Bisector

Back 61

A point, ray, line, line segment, or plane that intersects the segment at its midpoint

Front 62

Midpoint Formula

Back 62

x1 + x2 over 2 and y1 + y2 over 2

Front 63

Distance Formula

Back 63

D = square root of x2-x1 squared + y2 - y1 squared

Front 64

Angle

Back 64

Two different rays with the same endpoint

Front 65

Vertex

Back 65

The endpoint of an angle

Front 66

Measure

Back 66

Equal to the absolute value of the difference between the real numbers

Front 67

Acute Angle

Back 67

An angle less than ninety degrees and greater than zero degrees

Front 68

Obtuse Angle

Back 68

Angle less than 180 degrees and greater than ninety degrees

Front 69

Straight Angle

Back 69

An angle that is 180 degrees

Front 70

Congruent Angles

Back 70

Two angles that have the same measure

Front 71

Angle Bisector

Back 71

A ray that divides an angle into two angles that are congruent

Front 72

Complementary Angles

Back 72

Two angles with a sum of ninety degrees

Front 73

Supplementary Angles

Back 73

Two angles with a sum of 180 degrees

Front 74

Adjacent Angles

Back 74

Two angles that share a common vertex and side, but have no common interior points

Front 75

Linear Angles

Back 75

Two adjacent angles which have non-common sides that are opposite rays

Front 76

Vertical Angles

Back 76

Two angles whose sides form two pairs of opposite rays

Front 77

Polygon

Back 77

A closed plane figure with three or more sides

Front 78

Convex

Back 78

A polygon that has no line that contains an interior point in the polygon

Front 79

Concave

Back 79

A polygon that isn't convex

Front 80

n-gon

Back 80

Where n is the number of a polygon's sides, can also be used to name a polygon (more than 12)

Front 81

Equilateral Polygon

Back 81

A polygon in which all sides are congruent

Front 82

Equiangular Polygon

Back 82

A polygon where all angles in the interior are congruent

Front 83

Regular Polygon

Back 83

A convex polygon that is both equilateral and equiangular

Front 84

Conjecture

Back 84

An unproven statement that is based on observations

Front 85

Inductive Reasoning

Back 85

Used when you find a pattern in specific cases and then write a conjecture

Front 86

Counterexample

Back 86

A specific case for which the conjecture is false

Front 87

Conditional Statement

Back 87

A logical statement that has two parts, a hypothesis and a conclusion

Front 88

if-then form

Back 88

"If" is the hypothesis and "then" contains the conclusion

Front 89

Negation

Back 89

The opposite of the original statement

Front 90

Equivalent Statements

Back 90

When two statements are both true or both false

Front 91

Perpendicular Lines

Back 91

Two lines that intersect to form a right angle

Front 92

Biconditional Statement

Back 92

A statement that contains the phrase "if and only if"

Front 93

Deductive Reasoning

Back 93

Uses facts, definitions, accepted properties, and the laws of logic to form an argument

Front 94

Truth Value

Back 94

The value of a statement is either true or false

Front 95

Truth Table

Back 95

Shows the truth values for hypothesis and conclusion

Front 96

Proof

Back 96

A logical argument that shows a statement is true

Front 97

Two-column Proof

Back 97

Has numbered statements and corresponding reasons that show an argument in a logical order

Front 98

Theorem

Back 98

A statement that could be proven