1) Use Pythagoreans theorem




Approximately
2)To undo a exponent of 3, take a cube root

So the side's length is 9
3)
A)
For annual compounding let n=1 and t=2 (two years)
use the equation
Where A is return

So the annual return is $12,100
B)
For interest compounded quarterly let n=4 and t=2 (two years)



C)
For interest compounded monthly let n=12 and t=2 (two years)




D)
For interest compounded daily let n=365 and t=2 (two years)




So as the frequency of compounding increases it approaches a finite number. Notice how the increase gets smaller as we increase the frequency of compounding. So as the compounding frequency increases, it approaches a finite number. It actually approaches the continuous value of the continuous compound formula. Continuous compounding has the form
Where e is a constant e=2.71828...
So if it was contiuously compounded for 2 years at 10% then




So over 2 years it continuously compounds to $12,214.03
Hope this helps. Feel free to ask about any step.