Helpful Math Formulas

Square: s x s 

The area of a square is the length of one side squared. For example: if the area you want to cover is 3 feet long and 3 feet wide, to find the area, you multiple 3 times itself. You get “3 x 3 = 9 square feet.”

Rectangle: l x w

The area of a rectangle is the length times the width. For example: if the area you want to cover is 4 feet long and 6 feet wide, you multiple the 4 feet by the 6 feet. “You get 4 x 6 = 24 square feet.”

Circle: (pi) x (r x r)

The area of a circle is “pi” which is 3.14 multiplied by the radius squared. You find the radius of a circle by measuring it from one side straight down the middle to the other side. Then take that number and cut it in half. To square the radius, you multiply that number by itself. For example: The entire length down the middle of a circle is 16 inches. Cutting that number in half gives us the radius which is 8 inches. We then take that 8 inches and multiply it by itself (8x8) to get 64 inches. You then take that number, 64 inches and multiply it by “pi” which is 3.14. The answer is 200.96 inches. To find this number in “feet” we divide by 12 to give us 16.75 square feet for the circle.

Triangle: .5 x b x h

The area of a triangle is equal to one half of the base multiplied by the height. For example: if you have a triangle shape you want to cover that is 16 inches along the base and 40 inches high, you multiply the base of 16 by the 40 inches to get 640 inches. Then you multiply this by “.5” which is the same as dividing it in half or dividing the total by 2. In this example you get 320 inches. To find this number in “feet” divide the number by 12. The answer would then be 26.67 square feet. 

Trapezoid: .5 x (b1 + b2) x h

This formula can be used for many “odd” shaped rooms.

The area of a trapezoid (a shape that looks like a rectangle with a longer bottom, shorter top --or vica versa-- and sides that are angled in) is calculated by one half of the sum of the tops (or bases) multiplied by the height. For example: let’s say one side of your floor is 22 inches at the top and the bottom is 38 inches long with the total height between the two of 64 inches. First, add the two bases together (22 + 38) to give the total of 60 inches. You then multiply that total of 60 inches by the height of 64 inches to give you 3840 inches. Multiply the 3840 by “.5” which is the same as cutting it half or dividing it by 2. The answer is 1920 inches. Divide that number by 12 to give you the results in “feet.” In this example the answer is 160 square feet.