Question

find m∠1 (3x + 6)° 123° m∠1 = 57 video textbook get more help - review progress

Explanation:

Step1: Identify angle - relationship

The angle measuring $123^{\circ}$ and $\angle1$ are supplementary (linear - pair of angles), so their sum is $180^{\circ}$.

Step2: Calculate $m\angle1$

$m\angle1=180 - 123$
$m\angle1 = 57^{\circ}$

Answer:

$57^{\circ}$