Section 14 1 Angles Formed by Intersecting Lines

Section 14. 1: Angles Formed by Intersecting Lines 1

Objective: By following instructions, students will be able to: 1. Find the measures of angles formed by intersecting lines. 2

DEF: complementary angles – two angles whose sum of their measures is 90 degrees. DEF: supplementary angles – two angles whose sum of their measures is 180 degrees. COMPLEMENTARY ANGLES SUPPLEMENTARY ANGLES (adjacent and nonadjacent) 3

Def: linear pair – two adjacent angles whose non common sides are opposite rays. 4

Def: vertical angles– two angles whose sides form two pairs of opposite rays. • Angles are congruent 5

explain 1 Cross braces help keep the deck posts straight. Find the measure of each angle. a) b) and 6

Your-Turn #1 The measures of two vertical angles are given by the expressions (x + 3)° and (2 x - 7)°. Find the value of x. What is the measure of each angle? 7

DEF: complementary angles – two angles whose sum of their measures is 90 degrees. DEF: supplementary angles – two angles whose sum of their measures is 180 degrees. COMPLEMENTARY ANGLES SUPPLEMENTARY ANGLES (adjacent and nonadjacent) 8

explain 2 Use the diagram below to find the missing angle measures. Explain your reasoning. a) Find the measures of and . b) Find the measures of and . 9

Revisit Objective: Did we… 1. Find the measures of angles formed by intersecting lines? 10

HW: Sec 14. 1 pg 508 #s 1 -12 11