Question

what is the measure of this angle? m∠abc = ?°

Explanation:

Step1: Recognize the right - angle symbol

There is a small square at vertex \(B\) in \(\angle ABC\).

Step2: Recall the measure of a right angle

By definition, a right angle measures \(90^{\circ}\). So \(m\angle ABC = 90^{\circ}\).

Answer:

90