Help Explain how to set up the equation that solves it PLEASE!

Check page 7 of this. If it is confusing, I will try to work you through the process.

http://missharvey.weebly.com/uploads/4/4/8/2/4482376/t3.pdf

This is still confusing

After 2 hours:

RE^2 =18^2+24^2     (24 side length- 6 BE= 18)

RE=30

PR^2=24^2+24^2

PR=33.94112.....

Cos(PER)=30^2+30^2-33.9411...^2 / 2 (30) (30)

cos(PER) = 0.36

acos (0.36) = Angle PER

PER = 68.899803975907 degrees

HOPE THIS IS IT....... Please confirm

Conside the line from E to RC that is parallel to BC.     Let the point of intersection be X

EX=24

XR=24-6=18

find ER

\(ER=\sqrt{24^2+18^2}\\ ER=\sqrt{900}\\ ER=30 \)

Now PR is just the diagonal of one side of the square

\(PR=\sqrt{24^2+24^2}\\ PR=\sqrt{1152}\\ \)

Now I have all 3 sides of the triangle so I can use cosine rule to find the angle between them

the sides are      \(30, \quad30, \quad \sqrt{1152}\)

\(1152=900+900-2*900*Cos(PER)\\ 1152=1800-1800*Cos(PER)\\ -648=-1800*Cos(PER)\\ 0.36=Cos(PER)\\ \angle{PER}=cos^{-1}0.36=68.8998^\circ=68^\circ54' \)

That is assuming I've not made any stupid mistakes.

You beat me to it StarStrike!

Good Work!