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35 Cards in this Set
- Front
- Back
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4 formulas for finding angle measures of polygons
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CONVEX: sum of int. angles=
(n-2)180 sum of ext= 360 REGULAR: 1 int. angle= (n-2)180/n 1 ext.= 360/n |
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Triangle proportionality thm
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if a line is parallel to one side of the other 2 sides in 2 distinct pts, then it separates 3 sides into segments of proportional lengths
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exterior angle of a triangle
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an angle formed by one side of the triangle and the extension of another side
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concurrent lines
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when 3 or more lines intersect at a common point
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rectangle
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a quadrilateral with 4 right angles. opp sides of rectangle congruent.
so rectangle is a square |
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point of concurrency
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the point of intersection of concurrent lines
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equiangular triangles
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all three angles are congruent
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remote interior angles of a triangle
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the interior angles of a triangle are not adjacent to a given exterior angle
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square
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a quadrilateral that is both a rectangle and a rhombus
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three special segments of a triangle
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median, altitude, angle bisector
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incenter
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the angle bisectors of a triangle that are concurrent, this is their point of concurrency
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convex/ concave polygons
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if any line containing a side passes through the interior of the polygon, then the polygon is concave, otherwise, convex
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perpendicular bisector
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a line segment or ray that passes through the midpoint of the side and is perpendicular to that side
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trapezoid
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quadrilateral with exactly one pair of parallel sides called bases. non parallel sides called legs
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altitude
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a segment from a vertex perpendicular to the line containing the opp side
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regular polygon
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convex polygon in which all sides are congruent and all angles are congruent
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rhombus
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quadrilateral with 4 congruent sides. opp and consecutive sides congruent. perpendicular diagonals. diagonals bisect vertex angles
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scale factor
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when you compare the lengths of corresponding sides of similar figures, then this is the ratio
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similar polygons. when are they similar?
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if corres. angles are congruent and corres. sides are proportional
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right triangle
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one angle that is 90 degrees
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circumcenter
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the point of concurrency of the perpendicular bisector of a triangle
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equilateral triangle
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all sides are congruent
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median of a trapezoid
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the segment that joins the midpoints of the legs of the trapezoid
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parallelogram
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a quadrilateral with both pairs of opp sides parallel
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proportions
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an equation stating that two ratios are =
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ratio
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a comparison of two quantities using division expressed as a/b or a:b
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acute triangle
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all three angles are less than 90 degrees
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isosceles trapezoid
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a trapezoid with congruent legs
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obtuse triangle
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one angle over 90 degrees
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isosceles triangle
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at least 2 sides are congruent
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orthocenter
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the common point at which the altitudes of a triangle intersect
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scalene triangle
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no congruent sides
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centroid
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the common point where the medians intersect
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median
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a segment whose endpoints are a vertex of the triangle and the midpoint of the opp side
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three similarity patterns
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AA, SAS, SSS
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