Question

what is m∠a? m∠a = 66 choose 57 66 113

Explanation:

Step1: Identify triangle type

The triangle has two equal - length sides (marked with the same cross - hatch), so it is an isosceles triangle. In an isosceles triangle, the base angles are equal.

Step2: Recall angle - sum property of a triangle

The sum of the interior angles of a triangle is 180°. Let $\angle B=\angle C = 57^{\circ}$.

Step3: Calculate $\angle A$

We know that $\angle A+\angle B+\angle C=180^{\circ}$. Substitute $\angle B = 57^{\circ}$ and $\angle C = 57^{\circ}$ into the equation: $\angle A=180^{\circ}-\angle B - \angle C=180^{\circ}-57^{\circ}-57^{\circ}=66^{\circ}$.

Answer:

$66^{\circ}$