Square Root Calculation: Finding Side Length of a 400-Unit² Square

Question

A square has an area of 400.

How long are its sides?

00:00 Find the side of the square

00:05 We'll use the formula for calculating the area of a square (side squared)

00:11 We'll substitute appropriate values and solve for the side

00:16 Extract the root

00:21 When extracting a root there are always 2 solutions

00:26 The length of the side must be greater than 0

00:31 And this is the solution to the problem

The area of the square is equal to the length of the square raised to the second power.

That is:

$A=L^2$

Since we know that the area of the square is equal to 400, we perform the formula as follows:

$400=L^2$

We solve the square root:

$\sqrt{400}=L$

$L=20$

The side of the square is equal to 20.

$20$