What is 157609^(1/2)?

One way to attack this problem is to consider squaring the answer choices. When squared, the right answer will be 157609. We want to minimize calculation, so we want to look for shortcuts.

First, if the square of a number ends in 9 then the number itself will end in 3 or 7. So B and C are gone. We could have also noticed that both B and C are even, so their squares will also be even.

E, 403, is pretty close to a number that's easy to work with, 400, so let's consider E next. 400^2 = 160000, so 403^2 will be bigger still. Our number is smaller, so E is gone.

If we start multiplying A, 323, out the long way we find that the tens digit is 2, not 0. Eliminate.

D is all that's left.