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Question #N109

In the figure below, triangle ABC is isosceles with AB = AC, and the measure of angle BAC is 40 degrees. What is the measure of angle ABC?

A. 40

B. 70

C. 80

D. 100

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Correct Answer is: B

Since triangle ABC is isosceles, angle ABC and angle ACB have the same measure. The sum of the measures of the angles in a triangle is 180 degrees. Therefore, the measure of angle ABC is (180 - 40)/2 = 70 degrees.