A triangle has two corners with angles of pi / 6 π6 and (5 pi )/ 8 5π8. If one side of the triangle has a length of 15 15, what is the largest possible area of the triangle?

1 Answer
Oct 21, 2017

Largest possible area = 126.5489

Explanation:

Three angles are pi/6, (5pi)/8, (5pi)/24π6,5π8,5π24
Least angle is pi/6π6 which will correspond to side of length 15 to get maximum area.
C/ sin (/_C ) = A / sin( /_A ) = B / sin ( /_B)Csin(C)=Asin(A)=Bsin(B)
C/ sin ((5pi)/8) = A / sin ((5pi) / 24)= 15 / sin (pi/6)Csin(5π8)=Asin(5π24)=15sin(π6)

C= (15 * sin ((5pi)/8))/sin (pi/6) = 27.7164C=15sin(5π8)sin(π6)=27.7164

A = (5 * sin ((5pi)/24))/sin (pi/6) = 18.2628A=5sin(5π24)sin(π6)=18.2628

Semi Perimeter of Delta ABC s = (15 + 27.7154 + 18.2628) / 2 = 30.49

s - a = 30.49 - 27.7164 = 2.7732
s - b = 30.49 - 15 = 15.49
s - c = 30.49 - 18.2628 = 12.2272

Area of Delta ABC = sqrt(s(s-a)(s-b)(s-c))

Area of Delta ABC = sqrt (30.49 * 2.7732 * 15.49 * 12.2272) = **126.5489**