1)
use Pythagoras, so that
[tex] {18}^{2} - {10}^{2} = 224[/tex]
the square root if 224 is 14.96662955
so roughly, she needs 15ft for the remaining side.
15+10+18=43
so the answer is c.
2)
first calculate the length through the pond
36^2+49^2=3697
square root of 3697 =60.80296045
36+49=85
85-60.80296045=24.19703955
so he saves about 24.2m