Okay here:
Let L be the length and W the width of the rectangle.
1. w=2•L
2. 2L+2W=36
Substitute eq. 1 into eq. 2,
2L+2•(2•L)=36
2L+4L=36
6L=36
L=9
Not done yet, then from eq. 1,
W=2•L
W=2•9
W=18 <------- Your answer. :)
Both systems will have the same value of x's.
D. Since the dark part of the boomerang is on the different side, it had to have been rotated
But you're already done....
