Answer:
70
Step-by-step explanation:
840 / 12 = 70
we know that
Area of the circle is equal to

where
r is the radius
in this problem



therefore
the answer is the option
d. 113.04 sq. in.
You would have to be 30 because multiples of 5 would only be 25 and 30 inbetween those numbers, and 25 is not an even number which it must be if you can say the number counting by 2s
Answer:
Nina practiced the viola for 11.25 hours last week.
Step-by-step explanation:
Juan practiced the violin for 9 hours last week. For each 3 hours that he practices the violin, he practices 2.5 hours of cello. So
3h violin - 2.5h cello
9h violin - xh cello


He practiced 7.5 hours of cello, the same as Nina.
For every 3 hours Nina spends practicing the viola she practices the cello for 2 hours. So:
3h viola - 2h cello
xh viola - 7.5h cello



Nina practiced the viola for 11.25 hours last week.