Geometry) What is the measure of angle 1? m∠1=__________°.

Question

What is the measure of angle 1?

m∠1=__________°.

Triangle ABC is shown. There is a ray drawn from A through C, creating an exterior angle which is labeled angle 1. Angles A is marked as a right angle and angle B has a measure of 45 degrees.

Enter your answer as the number that correctly fills in the blank in the previous sentence, like this: 42

Answer 1

Klauss,

Ok so lets first determine all the angles of the triangle.

Given:

Angle A = 90

Angle B = 45

Angle C = ?

If we add up all the angles of any triangle, we should get 180 degrees.

Therefore, Angle C = 90 (angle A) - 45 (angle B) = 45 degrees.

Since there was a ray drawn from A through C the exterior angle of angle C is angle 1.

Any straight line should equal to 180 degrees.

Therefore, angle 1 = 180 - angle C = 135

Answer: angle 1 = 135 degrees