Seventh Grade Geometry Unit 5

Warm Up Write an equation to solve for x. The angle is a right angle. Then find the two angle measurements. 6x + 3x = 90 9x = 90 x = 10 Plug 10 back in for each x to find the two angles. 6(10) = 60º 3(10) = 30º 6xº 3xº

MCC7.G.5. Use facts about supplementary, complementary, vertical, and adjacent angles in a multi-step problem to write and solve simple equations for an unknown angle in a figure.

Essential Questions How can I use the special angle relationships – supplementary, complementary, vertical, and adjacent – to write and solve equations for multi-step problems?

Solve for x and then find the angle measurements. 7x + x + 20 = 180 8x + 20 = 180 x = 20 7(20) = 140º (20) + 20 = 40º

Solve for x and then find the angle measurements. 2x = 5x – 108 108 = 3x 36 = x 2(36) = 72º 5(36) – 108 = 72º

If one angle in a pair of vertical angles measures 70° and the other measures (3n – 8) , what is the value of n? 3n – 8 = 70 n = 26

One of two complementary angles has a measure that is 4 times that of the other angle. Which could be used to find n, the degree measure of the smallest angle? a. 4n = 90 b. n + 4n = 90 c. 4n = 180 d. n + 4n = 180

The measure of angle 2 is two times larger than measure of angle 1. 3 4 Classify the following pairs of angles. Use each of the following terms only once: supplementary, adjacent, and vertical. Angle 1 and angle 2 ________________ Angle 1 and angle 3 ________________ Angle 2 and angle 3 ________________ Find the measures of all 4 angles. Supplementary or Adjacent Vertical Adjacent or Supplementary n + 2n = 180 m<1 = 60° m<2 = 120° m<3 = 60° m<4 = 120°

Closing Write an equation to solve for x and then find the algebraic angle. 9x – 4 = 140 x = 16 9x – 4 9(16) – 4 140º