Well, first let's go ahead and organize this out...

So, you can't really do anything with the equation.
Why?

X cannot divide/cancel out anything, neither can -1.
So you're just left with the equation:

(not sure if you're missing any part of the equation PM me if you are)
Ratio is 1: 2:3
longest side = 12
12 / 3 = 4
4/2 = 2
shortest side is 2
Step-by-step explanation:
the answer is 5 percentage because the formula is 100 * 400 over 4000 * 2
Both are 117
1 and 117 are opposite so it's equal
2 is the same size
Based on the given condition, since the rectangle is inscribed in a circle given the length to be 3x, the width can be approximated by taking the right triangle formed by the radius and the w/2, sin 45 = w/2/r, which is equal to w = 2r sin45, therefore the Area of the inscribed rectangle = LxW = (3x)(2rsin45)