Question

a. x 40° 80°

Explanation:

Step1: Recall angle - sum property of a triangle

The sum of the interior angles of a triangle is 180°.

Step2: Set up an equation

Let the unknown angle be \(x\). Then \(x + 80^{\circ}+40^{\circ}=180^{\circ}\).

Step3: Solve for \(x\)

\(x=180^{\circ}-(80^{\circ} + 40^{\circ})\).
\(x = 180^{\circ}-120^{\circ}\).
\(x = 60^{\circ}\).

Answer:

\(60^{\circ}\)