I believe I already answered this question... did I get it wrong?
AB + CD = BC + DA
<span>Where A, B, C, and D are points on the quad, and AB is the length of the line A to B, etc. </span>
<span>Since you know three sides, you can easily solve for the fourth. </span>
9^2/9^7
when dividing powers, we subtract the exponents
9^(2-7)
9^ (-5)
a negative exponent flips from the numerator to the denominator
1/ 9^5
Choice D