Question

find the longest side of △abc, given that m∠c = 103°, m∠b = 30°, and m∠a = 47°.

Explanation:

Step1: Identify largest angle

The angles are $m\angle C=103^\circ$, $m\angle A=47^\circ$, $m\angle B=30^\circ$. The largest is $m\angle C=103^\circ$.

Step2: Match to opposite side

In a triangle, the longest side is opposite the largest angle. $\angle C$ is opposite side $AB$.

Answer:

$AB$