A triangle has sides A, B, and C. The angle between sides A and B is π4. If side C has a length of 4 and the angle between sides B and C is 3π8, what are the lengths of sides A and B?

1 Answer
Jan 6, 2016

The final answer is A = B = 42

Explanation:

We have two angles π4 and 3π8 so by adding them and subtracting the sum from π (π=180 = the sum of the angles of a triangle). The third angle is π(3π8+π4) = 3π8.

From the angles, we can infer that the triangle is isosceles, and we already know that thebetweenAandB=thebetweenAandC, by exclusion (since thebetweenAandBthebetweenBandC). Therefore, A=B.
sinbetweenAandB=CA=sin(π4)=12
4A=12

A=42