Geometry, Complementary Equals 90 and Supplementary Equals 180 Practice
Find missing angle measures using angle relationships
Geometry, Complementary Equals 90 and Supplementary Equals 180 Practice
Find missing angle measures using angle relationships
Geometry - Grade 6-8
- 1
Angle A measures 35 degrees. Angle B is complementary to Angle A. What is the measure of Angle B?
Subtract the given angle from 90 degrees.
Angle B measures 55 degrees because complementary angles add to 90 degrees, and 90 - 35 = 55. - 2
Angle C measures 112 degrees. Angle D is supplementary to Angle C. What is the measure of Angle D?
Angle D measures 68 degrees because supplementary angles add to 180 degrees, and 180 - 112 = 68. - 3
Two angles are complementary. One angle measures 27 degrees. Find the measure of the other angle.
Complementary means the two angle measures have a sum of 90 degrees.
The other angle measures 63 degrees because 90 - 27 = 63. - 4
Two angles form a straight line. One angle measures 46 degrees. What is the measure of the other angle?
The other angle measures 134 degrees because angles that form a straight line are supplementary, and 180 - 46 = 134. - 5
Classify the pair of angles as complementary, supplementary, or neither: 40 degrees and 50 degrees.
Add the two angle measures and compare the sum to 90 and 180.
The angles are complementary because 40 + 50 = 90. - 6
Classify the pair of angles as complementary, supplementary, or neither: 73 degrees and 107 degrees.
The angles are supplementary because 73 + 107 = 180. - 7
Classify the pair of angles as complementary, supplementary, or neither: 25 degrees and 55 degrees.
Check whether the sum equals exactly 90 or exactly 180.
The angles are neither complementary nor supplementary because 25 + 55 = 80, which is not 90 or 180. - 8
In the diagram, two adjacent angles form a right angle. One angle is 38 degrees and the other angle is x degrees. Write and solve an equation to find x.
The equation is 38 + x = 90. Solving gives x = 52, so the missing angle measures 52 degrees. - 9
In the diagram, two adjacent angles form a straight angle. One angle is 125 degrees and the other angle is y degrees. Write and solve an equation to find y.
A straight angle measures 180 degrees.
The equation is 125 + y = 180. Solving gives y = 55, so the missing angle measures 55 degrees. - 10
The measure of an angle is x degrees. Its complement is 18 degrees. Write and solve an equation to find x.
The equation is x + 18 = 90. Solving gives x = 72, so the angle measures 72 degrees. - 11
The measure of an angle is n degrees. Its supplement is 141 degrees. Write and solve an equation to find n.
Supplementary angles add to 180 degrees.
The equation is n + 141 = 180. Solving gives n = 39, so the angle measures 39 degrees. - 12
A vertical ray stands on a horizontal line, making a 90 degree angle on each side of the ray. One of the 90 degree angles is split into two angles labeled 64 degrees and z degrees. Find z.
The angle z measures 26 degrees because the two angles make a right angle, and 90 - 64 = 26.