A triangle has sides A, B, and C. The angle between sides A and B is pi/4 and the angle between sides B and C is pi/12. If side B has a length of 10, what is the area of the triangle?

1 Answer
Mar 27, 2018

color(brown)(A_t = (1/2) * a * b * sin C = 10.6 " sq units"

Explanation:

hat A = pi/12, hat C = pi/4, b = 10

hat B = pi - pi/12 - pi/4 = (2pi)/3

![http://www.dummies.com/education/math/trigonometry/laws-of-sines-and-cosines/](useruploads.socratic.org)

Applying the law of sines,

a = (b * sin A ) / sin B = (10 * sin (pi/12)) / sin ((2pi)/3) ~~ 3 " units"

"Area of the triangle " A_t = (1/2) * a * b * sin C

color(brown)(A_t = (1/2) * 3 * 10 * sin (pi/4) = 10.6 " sq units"