A triangle has sides A, B, and C. The angle between sides A and B is pi/4π4. If side C has a length of 12 12 and the angle between sides B and C is pi/12π12, what is the length of side A?

1 Answer
Sep 30, 2016

a ~~ 4.39a4.39

Explanation:

Using the notation where the sides are the lowercase letters, a, b, and c and the opposite angles are the uppercase letters, A, B, and C. The law of sines is:

a/sin(A) = b/sin(B) = c/sin(C)asin(A)=bsin(B)=csin(C)

We are given:
c = 12, C = pi/4 and A = pi/12c=12,C=π4andA=π12

Using the first and last part of the law of sines:

a/sin(A) = c/sin(C)asin(A)=csin(C)

a = (12sin(pi/2))/sin(pi/4)a=12sin(π2)sin(π4)

a ~~ 4.39a4.39