Area of a square living room is 256 ft2, what is the length of the room

When you calculate area, you need to multiply the side of the rectangle together. As this is a square this is the same as just squaring one side. Therefore, in order to calculate the length you need to reverse the squareing by square rooting the area:

√256 = 16 ft

Since the living room is square, the length and the width of the room are equal. That means all you have to do is find the square root of 256, which is 16.