If angle a has a measurement of 42° and is complementary to angle b, what's the measure of angle b?

B =48

Explanation:

To solve this problem we need to know that ALWAYS the sum of complementary angles are equeal to 90.

If A is complementary to angle B, we can affirm that:

A+B=90.

Given that A=42, solving for B:

B = 90 - A = 90 - 42 = 48

Then, the measure of angle B is 48.