Question

1. if m∠1 = 140, what is m∠3? 90° 130° 50° 40° the figure is not drawn to scale.

Explanation:

Step1: Find the measure of ∠2

Since ∠1 and ∠2 are supplementary (a straight - line is 180°), if m∠1 = 140°, then m∠2=180 - 140.
m∠2 = 180 - 140=40°

Step2: Use the angle - sum property of a right - triangle

In the right - triangle, one angle is 90° and another is ∠2. The sum of the interior angles of a triangle is 180°. Let m∠3 be the unknown angle. Then m∠3=180-(90 + m∠2).
Substitute m∠2 = 40° into the formula: m∠3=180-(90 + 40)=50°

Answer:

50°