A triangle has sides A, B, and C. The angle between sides A and B is (pi)/6. If side C has a length of 8 and the angle between sides B and C is (7pi)/12, what are the lengths of sides A and B?

1 Answer
Jun 1, 2018

a=4*sqrt(2)*(1+sqrt(3)),b=8sqrt(2)

Explanation:

The third angle is given by pi-9pi/12=pi/4

By the Theorem of sines we get

sin(pi/6)/sin(7*pi/12)=8/a
so

a=8*sin(7*pi/12)/sin(pi/6)

and
sin(pi/4)/sin(pi/6)=b/a

so
b=8*sin(pi/4)/sin(pi/6)#

note that
sin(7*pi/12)=1/4*sqrt(2)*(1+sqrt(3))
sin(pi/6)=1/2
sin(pi/4)=sqrt(2)/2