Question

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

Explanation:

Step1: Identify the scale

The protractor has two scales. We need to use the outer scale as the angle is measured from the \(0^{\circ}\) mark on the outer scale.

Step2: Read the angle

The ray \(BC\) is at \(0^{\circ}\) (outer scale) and ray \(BA\) is at \(290^{\circ}\) (outer scale). But since we measure the smaller angle between the two rays, we calculate \(360^{\circ}-290^{\circ}\).
$$360 - 290=70$$

Answer:

\(70\)