Two corners of a triangle have angles of (3 pi ) / 8 3π8 and pi / 4 π4. If one side of the triangle has a length of 7 7, what is the longest possible perimeter of the triangle?

1 Answer
Dec 20, 2017

Longest possible perimeter P = 25.2918

Explanation:

Given : /_ A = pi /4, /_B = (3pi)/8:A=π4,B=3π8

/_C = (pi - pi /4 - (3pi)/8 ) = (3pi)/8 C=(ππ43π8)=3π8

To get the longest perimeter, we should consider the side corresponding to the angle that is the smallest.

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

7 / sin (pi/4) = b / sin ((3pi)/8) = c / sin ((3pi)/8)7sin(π4)=bsin(3π8)=csin(3π8)

It’s an isosceles triangle as /_B = /_C = ((3pi)/8)B=C=(3π8)

:. b = c = (7 * sin ((3pi)/8)) / sin (pi/4) = 9.1459

Longest possible perimeter P = 7 + 9.1459 + 9.1459 = 25.2918