Question

3 use triangle angle sum theorem to find the measure of <1? <1= 45

Explanation:

Step1: Recall angle - sum theorem

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

Step2: Set up equation

Let the measure of angle 1 be $x$. Then $x + 76^{\circ}+59^{\circ}=180^{\circ}$.

Step3: Solve for $x$

$x=180^{\circ}-(76^{\circ} + 59^{\circ})=180^{\circ}-135^{\circ}=45^{\circ}$.

Answer:

$45^{\circ}$