Two corners of a triangle have angles of (7 pi )/ 12 7π12 and pi / 4 π4. If one side of the triangle has a length of 8 8, what is the longest possible perimeter of the triangle?

1 Answer
Feb 19, 2018

Longest possible perimeter of the triangle is

color(blue)(P + a + b + c ~~ 34.7685P+a+b+c34.7685

Explanation:

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hatA = (7pi)/12, hatB = pi/4, side = 8ˆA=7π12,ˆB=π4,side=8

To find the longest possible perimeter of the triangle.

Third angle hatC = pi - (7pi)/12 - pi/4 = pi/6ˆC=π7π12π4=π6

To get the longest perimeter, smallest angle hatC = pi/6ˆC=π6 should correspond to side length 8#

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

a = (c * sin A) / sin C = (8 * sin((7pi)/12)) / sin (pi/6) = 15.4548a=csinAsinC=8sin(7π12)sin(π6)=15.4548

b = (c * sin B) / sin C = (8 * sin(pi/4) )/ sin (pi/6) = 11.3137b=csinBsinC=8sin(π4)sin(π6)=11.3137

Longest possible perimeter of the triangle is

color(blue)(P + a + b + c = 15.4548 + 11.3137 + 8 = 34.7685P+a+b+c=15.4548+11.3137+8=34.7685