Question

estimate the measure of this angle within 10°.

Explanation:

Step1: Visual - estimate the angle

A right - angle is 90°. This angle is much smaller than a right - angle. A 30° angle is a common angle for estimation. By comparing the given angle with known angles like 30°, 45°, 60°, 90°, we can see that this angle is close to 20°.

Answer:

20