Question

if ∠bcd measures 142° what is the measure of ∠acb? a) 38° c) 142° b) 48° d) 180°

Explanation:

Step1: Identify angle - relationship

$\angle BCD$ and $\angle ACB$ are supplementary angles.

Step2: Use supplementary - angle formula

Supplementary angles add up to 180°. Let $m\angle ACB=x$ and $m\angle BCD = 142^{\circ}$. Then $x+142^{\circ}=180^{\circ}$.

Step3: Solve for $x$

$x=180^{\circ}- 142^{\circ}=38^{\circ}$

Answer:

A. $38^{\circ}$