Perfect Squares are numbers that are squares of whole numbers.
Here are some examples of perfect squares:
4 = 2 * 2
9 = 3 * 3
16 = 4 * 4
25 = 5 * 5
A Square Root of a number is one of its two equal factors.
A square root is basically a square, worked backwards.
The square root of 4 is 2.
The square root of 9 is 3.
The square root of 16 is 4.
The square root of 25 is 5.
While these are simple square roots, more complicated square roots are usually found using a calculator.
Here, the number 4 is under a radical, which means we are taking its square root. One thing to note is that either "2" or "-2" could be the square root of the number 4, because both 2 * 2 = 4, and (-2) * (-2) = 4. Most of the time we're only concerned with the positive square root, but in future lectures it will be important to recognize all possible roots.