Determining the amount of grain stored in a round bin, or a number of round bins, is useful not only in real life but for students trying to solve math problems as well. Farmers need to know exactly how much grain they have in their round bins so they can estimate yield as well as future crop needs. Farmers may store grain for cattle production or purposes other than selling the grain outright. Students learning the principles of geometry may find grain storage bin problems useful for learning how to determine the stored volume of cylindrical objects.
Measure the diameter and height of your round bin. Write the figures down on a sheet of paper.
Calculate the volume that your round bin stores by using the following formula: diameter x diameter x height x 0.785 = volume. The decimal is an approximation of the constant pi divided by 4. For example, a grain bin with a 30-foot diameter that is 24 feet tall holds 16,956 cubic feet of grain.
Translate the volume in cubic feet to a measurement in bushels by multiplying the result of Step 2 by 0.7786, or the following formula: cubic feet x 0.7786 = bushels. For example, 16,956 cubic feet x 0.7786 = 13,202 bushels.
If your round bin is not filled to capacity, modify the formula by measuring the depth of the grain instead of the height of the round bin. For example, if your round bin is 32 feet in diameter and 20 feet tall but is only filled to 12 feet with grain, your formula would be: 32 x 32 x 12 x 0.785 = 9,646 cubic feet or 7,510 bushels.