Question

find the measure of angle c. round to the nearest tenth.

Explanation:

Step1: Use the angle - sum property of a triangle

The sum of angles in a triangle is \(180^{\circ}\). Let \(\angle A = 120^{\circ}\), \(\angle B=40^{\circ}\), and \(\angle C\) be the unknown angle.
We know that \(\angle A+\angle B + \angle C=180^{\circ}\).
Substitute the values: \(120^{\circ}+40^{\circ}+\angle C = 180^{\circ}\).

Step2: Solve for \(\angle C\)

\(\angle C=180^{\circ}-(120^{\circ} + 40^{\circ})\)
\(\angle C=180^{\circ}-160^{\circ}\)
\(\angle C = 20^{\circ}\)

Answer:

\(20^{\circ}\)