A triangle has two corners with angles of pi / 12 π12 and (5 pi )/ 8 5π8. If one side of the triangle has a length of 1 1, what is the largest possible area of the triangle?

1 Answer
Dec 5, 2017

Area of largest possible triangle = color (red)(2.0056)=2.0056

Explanation:

Three angles are pi/12, (5pi)/8, (pi - (pi/12) + ((5pi)/8) =( 7pi)/24π12,5π8,(π(π12)+(5π8)=7π24

a/ sin A = b / sin B = c / sin CasinA=bsinB=csinC

To get the largest possible are, smallest angle should correspond to the side of length 1.

1 / sin (pi/12) = b / sin ((7pi)/24) = c / sin ((5pi)/8)1sin(π12)=bsin(7π24)=csin(5π8)

b = (sin ((7pi)/24)) / (sin (pi/12)b=sin(7π24)sin(π12)
b = 3.0653b=3.0653

c = (sin ((5pi)/8)) / (sin (pi/12))c=sin(5π8)sin(π12)
c = 3.5696c=3.5696

Semi perimeter s = (a + b + c) / 2 = (1+3.0653+3.5696)/2 = 3.8175s=a+b+c2=1+3.0653+3.56962=3.8175

s-a = 3.8175-1 = 2.8175sa=3.81751=2.8175
s-b = 3.8175-3.0653 = 0.7522sb=3.81753.0653=0.7522
s-c = 3.8175-3.5696 = 0.2479sc=3.81753.5696=0.2479

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

Area of Delta = sqrt(3.8175 * 2.8175 * 0.7522 * 0.2479) = color (red)(2.0056)