This section is to help you determine how much material to order, how long it will take to pump the water out of a pool or basement, or how much something weighs.
The first step in determining the volume of an object is to determine its square area in one plane. We will use a swimming pool that is 20' x 40' for an example. If we multiply the length by the width we get 20 x 40 =800 so the area is 800 square feet, To determine how many gallons of water is in the pool we to multiply that area by the average depth. We will use 4' for our imaginary pool, so 800 x 4 = 3200 cubic feet of water. There is 7.5 gallons in one cubic foot, so we must multiply 7.5 x 3200 to determine that our pool holds 24,000 gallons of water. If we wanted to know how much paint to buy we would need to know the total surface area, which would be the 800 square ft. on the bottom, plus the area of the walls. To determine the area of the walls, the perimeter 20+40+20+40=120 multiplied by the average depth 4x120=480. So we need to buy enough paint to cover 1280 square feet
These concepts can be applied to just about any shape or object. If the shape is irregular, just break it down into a series of familiar shapes, rectangles, circles, ellipses, or triangles, and add all of the areas together. Below is a list of the formulas for calculating the area of most shapes that you might encounter. To get volume, multiply the area by the depth, just remember to use all the same units, don't multiply feet by inches, etc.
Square or Rectangle Length times Width Circle 3.14 x Radius x Radius (1t R2)Circumference = 3.14 x the Diameter (1tD) Right Triangle Length x Height divided by 2 Ellipse 1t X major radius x minor radius
In order to apply the information we have now determined, we need to know some other useful information: