In a triangle suppose alpha 70 degree b 180 cm and c 200

In a triangle, suppose alpha - 70 degree, b = 18.0 cm, and c = 20.0 cm. Find the missing parts of the triangle.

Solution

a²=b²+c²-2bc cos alpha

a²=724-720 cos 70

a=21.86

Sin 70/21.86= sin Beta/18

sin beta=18 sin 70/21.8

Beta=50.70 degree

gamma=180-alpha-beta=59.3 degree