In triangle FGH, mF is 94°, mG is 49°, and mH is 37°. The exterior angles of triangle FGH are J, K, and L, and they are adjacent to F, G, and H, respectively.
What is mK?
A. 86°
B. 49°
C. 143°
D. 131°
The exterior angles theorem tells us that the measure of an exterior angle of a triangle is equal to the sum of the other two angles of the triangle. Since m∠G=94°, m∠K=180-94=131°.