Lines, Angles, and Triangles

SAT Math· difficulty 4/5

In triangle ABC, the exterior angle at C measures 115°115°. The interior angle at A is twice the interior angle at B. What is the measure of angle B?

  • A

    50°50°

  • B

    115°3\frac{115°}{3}

    check_circle
  • C

    65°65°

  • D

    57.5°57.5°

Explanation

Exterior angle at C = A + B = 115°115°. With A = 2B: 2B+B=1152B + B = 115, so 3B=1153B = 115, B=frac115°3B = \\frac{115°}{3}.

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