Use the Pythagorean theorem to find the height.
Height = sqrt(26^2-10^2)
Height = 24 cm
Volume = 20^2 x 24/3
Volume = 7,200 cm^3
No one can help you if you dont show us the work my dude. But the was to convert them is say you have 1/4 that is 25% of a whole. Sorry i couldnt help more repost the question with a link and people can help then.
For the first one...
1,15
2,30
3,20
and for the second one is the same as the first one.
EXTRA CREDIT:
Week one increases by 15, week two increases by 15 but week three decreases by 15. The total miles ran would be 15 miles
15+15=30 30-15=15 miles
Alternate interior angles I believe