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

1 Answer
Oct 18, 2017

Area of triangle A = sqrt(s (s-a) (s-b) (s - c))A=s(sa)(sb)(sc)

**A = 145.1551**A=145.1551

Explanation:

Three angles are pi/12, pi/8, (19pi)/24π12,π8,19π24
a/sin a = b / sin b = c / sin casina=bsinb=csinc
5/sin (pi/12) = b/sin (pi/8) = c /sin ((19pi)/24)5sin(π12)=bsin(π8)=csin(19π24)

b = (5* sin (pi/8))/sin (pi/12) = 7.3929b=5sin(π8)sin(π12)=7.3929

c = (5* sin ((19pi)/24)/sin (pi/12)=11.7604c=5sin(19π24)sin(π12)=11.7604

s = (a + b + c) /2 = (5+7.3928+11.7604)/2= 18.273s=a+b+c2=5+7.3928+11.76042=18.273
s-a = 13.273sa=13.273
s-b = 10.8801sb=10.8801
s-c = 6.5126sc=6.5126

Area of triangle A = sqrt(s (s-a) (s-b) (s - c))A=s(sa)(sb)(sc)

A = sqrt(18.273 * 13.273 * 10.8801 * 6.5126) = 145.1551A=18.27313.27310.88016.5126=145.1551