A triangle has sides A, B, and C. The angle between sides A and B is 3π4 and the angle between sides B and C is π12. If side B has a length of 7, what is the area of the triangle?

1 Answer
May 1, 2017
  1. Sum of angles in a triangle, followed by
  2. Sin rule

Explanation:

since we know 2 angles of the triangle and the length of one side of the triangle (assuming it is measured in centimetres), the first step we can take is

π - 3π4 - π12 = 3rd unknown angle, x

We can then apply the sin rule to find the length of either A or C (I'll go with C)

Csin(3π4) = 7sin(x)

area of the triangle = 0.5 (7)(C)sin(π12)