Question

Find the measure of the exterior angle in the following triangle. DUE SOON PLZ HELP WITH STEP BY STEP

Answer 1

Answer:

The measure of an exterior angle = 125°

Hence, option A is correct.

Step-by-step explanation:

As the given triangle is a right-angled triangle ΔABC.

Given the angles

• m∠A = 35°

• m∠C = 90°

We know that the sum of angles in a triangle is 180°.

Thus,

m∠A + m∠B + m∠C = 180°

substituting m∠A = 35° and m∠C = 90° in the equation

35° + m∠B + 90° =  180°

125 + m∠B = 180°

subtract 125 from both sides

125 + m∠B - 125 = 180° - 125

m∠B = 55°

Thus, the measure of angle B is:

m∠B = 55°

As the exterior angle of the given triangle is adjacent to m∠B = 55°.

We know that the exterior angle of a triangle is equal to the sum of two opposite interior angles.

Here,

∠A and ∠C are two opposite interior angles of the exterior angle.

Thus,

The measure of an exterior angle is equal to the sum of two opposite interior angles.

as

• m∠A = 35°

• m∠C = 90°

so

Exterior angle = m∠A + m∠C

                        = 35° + 90°

                        = 125°

Thus, the measure of an exterior angle = 125°

Hence, option A is correct.