The formula A=P (1+r)^2 gives the amount A in dollars that P dollars will grow to in 2 years at interest rate r (where r is given as a decimal), using compound interest. What interest rate will cause $2000 to grow to $2226.05 in 2 years?
The interest rate is ?%
Wow I don't even know where to start! Help!
The interest rate is ?%
Wow I don't even know where to start! Help!

You want $2000 to grow into $2226.05
Thus, your initial amount, P, will be $2000.
Your final amount after 2 years, A, will be $2226.05
We have:
2226.05 = 2000(1 + r)^2
(1 + r)^2 = 2226.05 / 2000
1 + r = sqrt(1.113025)
r = 1.055  1
r = 0.055
Thus, we have an interest rate of 0.055
In terms of percentage, this will be 5.5%
Thus, your initial amount, P, will be $2000.
Your final amount after 2 years, A, will be $2226.05
We have:
2226.05 = 2000(1 + r)^2
(1 + r)^2 = 2226.05 / 2000
1 + r = sqrt(1.113025)
r = 1.055  1
r = 0.055
Thus, we have an interest rate of 0.055
In terms of percentage, this will be 5.5%