Chapter 4 Geometry Flashcards 4.1  4.3
Terms
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 congruent polygons
 have congruent corresponding parts
 congruence statments
 [Triangle] ABC [is congruent to] [Triangle] DEF
 congruent triangles
 2 triangles are congruent if and only if their corresponding parts are congruent (CPCTC)
 THIRD ANGLE THEOREM
 if 2 angles of 1 triangle are congruent to 2 angles of another triangle, then the third angles are congruent.
 SSS Postulate
 if 3 sides of a triangle are congruent to the 3 sides of another triangle, then the two triangles are congruent
 SAS Postulate
 if 2 sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then the two triangles are congruent
 ASA Postulate
 If 2 angles and the included side of one triangle are congruent to two angles and the included side of another triangle, then the two triangles are congruent
 AAS THEOREM
 If two angles and a nonincluded side of one trianlge are congruent to two angles and the corresponding nonincluded side of another trianlge, then the triangles are congruent.
 polygon
 a polygon is a closed plane figure with at least 3 sides that are segments such that: the sides intersect exactly 2 other sides only at their endpoint no adjacent sides are collinear
 diagonal of polygons
 a segment that is drawn from 2 vertices that are not adjacent
 convex polygon
 has no diagonal with points outside the polygon
 concave polygon
 has at least 1 diagonal with the points outside the polygon
 equilateral polygon
 all sides are congruent
 equiangular polygon
 has all congruent angles
 regular polygon
 both equilateral and equiangular
 POLYGON ANGLE SUM THEOREM (PAST)

The sum of the measure of the angles of a convex ngon is:
*** s = 180(n2)  POLYGON EXTERIOR ANGLE THEOREM (PEAST)
 The sum of the measures of the exterior angles of a convex polygon, one at a vertex, equals 360
 standard form of a linear equation
 a linear equation can be written in the form Ax + By = C (standard form) where A, B, and C are real numbers and A & B do not equal 0; slope is A/B if in standard form
 slope intercept form
 a linear equation written in the form y = mx + b
 point slope form
 y  y1 = m (x  x1) where x1 and y1 are the coordinates of a point on the line and m is the slope

SPECIAL CASE:
Horizontal Lines  have an equation in the form y = b and a slope of 0

SPECIAL CASE:
Vertical Lines  have an equation in the form x = a and an undefined slope
 slope

The slope of a line is the ratio of its vertical rise to its horizontal run. The slope m of a line containing 2 points with coordinates (x,y) and (x1, y1) is given by the formula:
m = y2y1/x2x1  Slopes of a Parallel Lines
 2 non vertical lines have the same slope if and only if they are parallel
 Slopes of Perpendicular Lines
 2 nonvertical lines are perpendicular if and only i the product of their slopes equals 1; any horizontal line and vertical line are perpendicular