Her estimate is not reasonable.
Since she estimated 69%, you could do either of these options. You could...
A. Divide 242 (or .5) to show how much half off would be, then compare her estimate with half of 242 (121). OR...
B. Simply divide 242 by 69% (.69) and compaor her estimate to the exact amount (166.98).
I hope this helps!
(0,0), (1,1)
Basically, any point that is shaded.
That would be written as:

And the step-by-step equation would be:
→ we take the 2 to the right side of the equation and do the IO*
→we solve for 
→ final answer
*Ps - IO is not an existing term and stands for inverse operation. In this case, because when we take to 2 to the right side of the equation (the 2 is a power) it'll have to turn into a square root (because exponents and roots are inverse operations)
Hope it helped,
BioTeacher101
31 x 7.875 = 244.125
244.125 inches altogether