Question

Which of the following is a perfect square? A 127 B 100 C 13 D 102

Answer 1

Answer: 100.

Justification.

A perfect square is a number that can be expressed and the square of an integer.

In this case, 10^2 = 100, so 100 is a perfect square.

It is a good idea to memorize the first perfect squares. I recommend you memorize the squares of the numbers from 1 to 14. That will help you a lot in some standardized tests,which requires to answer some quesitons fast:

$1^2=1 2^2=4 3^2=9 4^2=16 5^2=25 6^2=36 7^2=49 8^2=64 9^2=81 10^2=100 11^2=121 12^2=144 13^2=169 14^2=196$

Answer 2

100 = 10 * 10 = 10^2