A triangle has two corners with angles of # pi / 6 # and # (5 pi )/ 8 #. If one side of the triangle has a length of #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)/24#
Least angle is #pi/6# which will correspond to side of length 15 to get maximum area.
#C/ sin (/_C ) = A / sin( /_A ) = B / sin ( /_B)#
#C/ sin ((5pi)/8) = A / sin ((5pi) / 24)= 15 / sin (pi/6)#

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

#A = (5 * sin ((5pi)/24))/sin (pi/6) = 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**#