For question 9 - It is stating that AE is equal to 38. So the length of the entire line is 38. We then need to look at which figures are actually useful to us, which in this case is AC which is 10. Therefore the answer is as simple as 38-10, which gives us an answer of 28 for the other half of the line, notated as CE.
I also agree with answer C
A=pir^2
a=pi13^2
a=169pi
a=530.66 square cm
Remember that there are 16 cups in a gallon.
The pipe leaks 1.5 cups each day, so in one week, or 7 days, the cup leaks 1.5 times 7 cups, which equates to 10.5 cups per week.
To find this number in gallons, divide 10.5 by 16.
This equals .65625 gallons per week.
Hope this helps!
~Chrys