Question

in the figure below, m∠1 = 42°. find m∠2.

Explanation:

Step1: Recognize angle - relationship

The two angles ∠1 and ∠2 are supplementary (form a straight - line), and the sum of supplementary angles is 180°.
$m\angle1 + m\angle2=180^{\circ}$

Step2: Substitute the value of ∠1

Given $m\angle1 = 42^{\circ}$, we substitute it into the equation:
$42^{\circ}+m\angle2 = 180^{\circ}$

Step3: Solve for ∠2

$m\angle2=180^{\circ}-42^{\circ}$
$m\angle2 = 138^{\circ}$

Answer:

$138$