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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.
6xº
3xº
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
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.
7xº
(x + 20)º
7x + x + 20 = 180
8x + 20 = 180
x = 20
7(20) = 140º
(20) + 20 = 40º
Solve for x and then find the angle measurements.
2xº
2x = 5x – 108
108 = 3x
36 = x
(5x -108)º
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.
2
1
4
3
Classify the following pairs of angles.
Use each of the following terms only once: supplementary, adjacent, and vertical.
Supplementary or Adjacent
Angle 1 and angle 2 ________________
Angle 1 and angle 3 ________________
Vertical
Adjacent or Supplementary
Angle 2 and angle 3 ________________
Find the measures of all 4 angles.
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