Question

lo: swbat solve problems using the angle sum t
dol: given a set of problems, students will correct theorem of triangles in at least 4 of 5 questions.

1. ethan was given a triangle with the following measurements: ∠a = 72° and ∠b = 55°. what is the measurement of ∠c?

a. 33°
b. 55°
c. 45°
d. 53°

Explanation:

Step1: Recall angle - sum theorem

The sum of the interior angles of a triangle is 180°. So, $\angle A+\angle B+\angle C = 180^{\circ}$.

Step2: Solve for $\angle C$

We can rewrite the formula as $\angle C=180^{\circ}-\angle A - \angle B$. Substitute $\angle A = 72^{\circ}$ and $\angle B = 55^{\circ}$ into the formula. Then $\angle C=180^{\circ}-72^{\circ}-55^{\circ}=53^{\circ}$.

Answer:

D. $53^{\circ}$