What are complementary and supplementary angles?

Complementary angles are two angles that add to ninety degrees.

Supplementary angles are two angles that add to one hundred and eighty degrees.

Sample problem one.

30 is the complement of what angle?

Step 1 30 + X = 90◦

Step 2 Subtract 30 from each side x= 60◦

Sample problem 2 What is the angle measure of X ?

Step 1 In a right triangle the two angles are complementary.

Step 2 90 – 68= 22◦

Sample problem 3

105◦ is the supplement of what angle?

Step 1 x + 105 = 180

Step 2 subtract 105 from each side x = 75◦

Sample problem 4

What is the angle measure of ∠x ?

Step 1 A straight line measures 180◦

Step 2 180 -65 = 115◦ is the measure of ∠x