Question

3
find the measure of the unknown angle (?) in the triangle, where two angles are 20° and 130°

Explanation:

Step1: Recall triangle angle sum rule

The sum of angles in a triangle is $180^\circ$.

Step2: Set up equation for unknown angle

Let the unknown angle be $x$.
$x + 20^\circ + 130^\circ = 180^\circ$

Step3: Calculate the unknown angle

$x = 180^\circ - 20^\circ - 130^\circ$
$x = 30^\circ$

Answer:

$30^\circ$