101 = (4x-3) EXPLAIN 1 Using Vertical Angles Read Explain 1 and complete Your Turn #1-3 (adapted from Lesson 4.1). Show all your work. You can use the Vertical Angles Theorem to find missing angle measures. Example Find the angle measures What is the measure of ZDEB? Find the value of x. mZAEC=m&DEB A 101 Vertical angles are congruent E Substitute angle measures D Add 3 on both sides (4x-3) B Divide by 4 on both sides 104 = 4x 26 = x So, the value of x is 26 and mLDEB = 101 2 What is the measure of LAED? What is the measure of CEB LAEDand LDEB form a linear pair, so they are supplementary. mZAED +mZDEB = 180 x+101 = 180 x = 79 MAED = 79 mZAED=m4CEB mZCEB = 79 Definition of supplementary angles Substitute angle measures Subtract 101 on both sides Substitute x for its angle measure Vertical angles are congruent Transitive Property Your Turn 1. Find the value of x. P 4(x+6) R T S (5x+11) 2. The measure of two verticle angles are 58 and (3x+4). Find the value of x.