Chapter 8 Polygons and Transformations.
VOCABULARYA straight angle measures 180°. A right angle measures 90°.Two angles are supplementary if the sum of their measures is 180°.Two angles are complementary if the sum of their measures is 90°.Two intersecting lines form two pairs of angles that do not share aside. These pairs are called vertical angles. Vertical angles alwayshave the same measure.Perpendicular lines are lines that intersect at a right angle.Parallel lines are lines in the same plane that do not intersect.When a line intersects two parallel lines, the measures ofcorresponding angles are equal, of alternate interior angles areequal, and of alternate exterior angles are equal.
Finding an Angle Measure<1 and <2 are supplementary, and m<2 =97°. Find m<1.Solutionm<1 +m<2 =180° Definition of supplementary anglesm<1 +97° =180° Substitute 97° for m<2.m<1 = 83° Subtract 97° from each side.