College Math Placement Practice Test 2026 - Free College Math Questions and Study Guide

Complementary angles are defined as two angles whose measures add up to 90 degrees. In this scenario, if one angle measures 30 degrees, you can find the measure of the other angle by subtracting the known angle from 90 degrees.

So, you would calculate:

90 degrees - 30 degrees = 60 degrees.

This calculation shows that the measure of the other angle is indeed 60 degrees. Hence, the correct answer reflects this calculation correctly.

The other potential answers do not satisfy the condition of complementary angles, as they either exceed 90 degrees or do not sum with 30 degrees to reach 90.