If an angle measures 30 degrees, what is its complementary angle?

• A. 30 degrees
• B. 60 degrees
• C. 90 degrees
• D. 120 degrees

Answer: (B)

To find the complementary angle of a given angle, you need to remember that complementary angles are two angles that add up to 90 degrees. In this case, you have an angle that measures 30 degrees.

To calculate the complementary angle, subtract the measure of the given angle from 90 degrees:

90 degrees - 30 degrees = 60 degrees.

This calculation shows that if one angle measures 30 degrees, the other angle that complements it must measure 60 degrees in order to meet the definition of complementary angles.

Thus, the complementary angle of a 30-degree angle is indeed 60 degrees, making it the correct answer.