Two corners of a triangle have angles of 5π8 and π12. If one side of the triangle has a length of 3, what is the longest possible perimeter of the triangle?

1 Answer
Oct 15, 2016

The maximum perimeter is 22.9

Explanation:

The maximum perimeter is achieved, when you associate the given side with the smallest angle.

Calculate the third angle:
24π2415π242π24=7π24

π12 is the smallest

Let angle A=π12 and the length of side a=3
Let angle B=7π24. The length of side b is unknown
Let angle C=5π8. The length of side c is unknown.

Using the law of sines:

The length of side b:

b=3sin(7π24)sin(π12)9.2

The length of side c:

c=3sin(5π8)sin(π12)10.7

P = 3 + 9.2 + 10.7 = 22.9