Question

Find the measure of ZJ, the smallest angle in a triangle

with sides measuring 11, 13, and 19. Round to the
nearest whole degree.
O 30°
O 34°
o 42°
O 47°

Answer 1

Make A the subject
2bc.cos(A) = b^2 + c^2 - a^2
cos(A) = (b^2 + c^2 - c^2) / (2bc)
cos(A) = (13^2 + 19^2 - 11^2) / (2 x 13 x 19) = 0.827935
A = 34 degrees