Two corners of a triangle have angles of ( pi )/ 3 π3 and ( pi ) / 4 π4. If one side of the triangle has a length of 5 5, what is the longest possible perimeter of the triangle?

1 Answer
Feb 19, 2018

Longest possible perimeter of the triangle is

color(brown)(P = a + b + c ~~ 17.9538P=a+b+c17.9538

Explanation:

To find the longest possible perimeter of the triangle.

Given hatA = pi/3, hatB = pi/4ˆA=π3,ˆB=π4, one side = 5side=5

hatC = pi - pi/3 - pi/4 = (5pi)/12ˆC=ππ3π4=5π12

Angle hatBˆB will correspond to side 5 to get the longest perimeter.

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a / sin A = b / sin B = c / sin CasinA=bsinB=csinC, applying sine law.

a = (b sin A) / sin B = (5 * sin (pi/3)) / sin (pi/4) = 6.1237a=bsinAsinB=5sin(π3)sin(π4)=6.1237

c = (b sin C) / sin B = (5 * sin ((5pi)/12)) / sin (pi/4) = 6.8301c=bsinCsinB=5sin(5π12)sin(π4)=6.8301

Longest possible perimeter of the triangle is

color(brown)(P = a + b + c = 6.1237 + 5 + 6.8301 ~~ 17.9538P=a+b+c=6.1237+5+6.830117.9538