Two corners of a triangle have angles of π8 and π6. If one side of the triangle has a length of 4, what is the longest possible perimeter of the triangle?

1 Answer
Jun 2, 2016

Longest possible perimeter is 17.519.

Explanation:

As two angles are π8 and π6, third angle is ππ8π6=24π3π4π2417π24.

For longest perimeter side of length 4, say a, has to be opposite smallest angle π8 and then using sine formula other two sides will be

4sin(π8)=bsin(π6)=csin(17π24)

Hence b=4sin(π6)sin(π8)=4×0.50.3827=5.226

and c=4×sin(17π24)sin(π8)=4×0.79340.3827=8.293

Hence longest perimeter is 4+5.226+8.293=17.519.