A triangle has sides A,B, and C. If the angle between sides A and B is (7pi)/127π12, the angle between sides B and C is pi/4π4, and the length of B is 7, what is the area of the triangle?

1 Answer
Jun 19, 2017

The area of the triangle is =33.5u^2=33.5u2

Explanation:

The angle between AA and CC is

=pi-(7/12pi+1/4pi)=π(712π+14π)

=pi-10/12pi=π1012π

=2/12pi=1/6pi=212π=16π

B=7B=7

We apply the sine rule

A/sin(1/4pi)=B/sin(1/6pi)Asin(14π)=Bsin(16π)

A=(Bsin(1/4pi))/sin(1/6pi)A=Bsin(14π)sin(16π)

The area of the triangle is

=1/2*A*B*sin(7/12pi)=12ABsin(712π)

=1/2*B*(Bsin(1/4pi))/sin(1/6pi)*sin(7/12pi)=12BBsin(14π)sin(16π)sin(712π)

=1/2*B^2*(sin(1/4pi))/sin(1/6pi)*sin(7/12pi)=12B2sin(14π)sin(16π)sin(712π)

=1/2*49*1.366=12491.366

=33.5=33.5