Question

∠abc is a straight angle. which equation can be used to find the measure of the unknown angle? image of angle with 45° and? at point b, a---b---c straight line, and bd making 45° with ba options: 180 ÷ 45 = □, 45 + 180 = □, 45 × 180 = □, 180 - 45 = □

Explanation:

Step1: Recall straight angle measure

A straight angle $\angle ABC = 180^\circ$.

Step2: Set up angle sum equation

The angle $\angle ABD = 45^\circ$, let the unknown angle be $x$. Then $45^\circ + x = 180^\circ$.

Step3: Rearrange to solve for $x$

Rearrange the equation to isolate $x$: $x = 180 - 45$.

Answer:

$180 - 45 = \square$