A triangle has sides A, B, and C. The angle between sides A and B is pi/3π3 and the angle between sides B and C is pi/12π12. If side B has a length of 5, what is the area of the triangle?

1 Answer
May 19, 2016

Area of triangle is 2.902.90

Explanation:

The third angle opposite sides AA and CC is

pi-pi/3-pi/12=(12-4-1)pi/12=5pi/12ππ3π12=(1241)π12=5π12 and it has side B=5B=5 opposite it.

As side AA has angle opposite it pi/12π12, using sine formula, we get

A/sin(pi/12)=B/sin((5pi)/12)Asin(π12)=Bsin(5π12) or

A=Bxxsin(pi/12)/sin((5pi)/12)=5xx0.2588/0.9659=1.34A=B×sin(π12)sin(5π12)=5×0.25880.9659=1.34

Hence area of triangle is 1/2xx5xx1.34xxsin(pi/3)12×5×1.34×sin(π3)

= 1/2xx5xx1.34xx0.866=2.9012×5×1.34×0.866=2.90