Question

how are $\angle 1$ and $\angle 2$ related?
complete the equation.
$m\angle 1 + m\angle 2 = \square^\circ$

Explanation:

Step1: Identify the angle type

∠1 is a right angle (marked with a square), so $m\angle1 = 90^\circ$.

Step2: Sum the angles

∠1 and ∠2 form a straight angle. A straight angle is $180^\circ$, so $m\angle1 + m\angle2 = 180^\circ$.

Answer:

180