How to Find Surface Areas of Objects
Trying to determine the surface areas of different shapes may seem confusing, but there is no reason for uncertainty. There are well-defined mathematical formulas to calculate the dimensions of shapes, including the surface area of rectangles, parallelograms and even triangular or circular shapes. If any given object is made up of more than one basic shape, simply calculate for one of the shapes at a time, and then add the different measurements together. Does this Spark an idea?
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Instructions
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Calculating Square Boxes and Flat-Sided Objects
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The basic formula for the area of a square box is 6*(Length * Width). Measure the length and width of one side. Multiply the length times the width. Multiply that number by 6 for the total surface area. When one or more sides are completely blocked from use, such as the bottom of a mounted box, then only multiply by the number of sides you can physically access.
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2
The basic formula to calculate area for a rectangular box shape is 2*(AB)+2*(BC)+2*(AC). Multiply the length and width of the top to determine the AB measurement. Calculate the BC measurement by multiplying the length and width of one end. Multiply the length and width of the front to get the AC measurement. Multiply each of the numbers you calculated by 2, and add the results together for the total surface area.
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3
The formula to calculate the area of a trapezoid is ((A+B)*Height)/2. Measure the longest and shortest sides, and add them together. Multiply that number by the distance between those two sides. Divide the answer by 2, and you have the area of the trapezoid. Double this number (to represent the top and bottom). Calculate each side by multiplying the length by the width. Add all of the calculations together for the total surface area.
Calculating the Surface Area for Cylinders
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The formula to calculate the surface area of a cylinder is (2*pi*(r^2))+(2*pi*r*h). Measure from the center of the circle to the outside edge to determine the radius (r). Multiply the radius by itself (r*r). Multiply that number by pi (3.14 is close enough). This is the surface area of one end of the cylinder.
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Take the number from the previous step and multiply it by 2. This provides you with the total surface area of the round ends of the cylinder.
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Measure the height of the cylinder. Multiply the height times the radius. Multiply that number by pi (3.14), and multiply the result by 2. Add the surface area for the ends, and you have the total surface area of the cylinder.
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Tips & Warnings
Draw the shape you are calculating, and mark each measurement down as it is made.
Determine the lengths and widths, and then use an online calculator to work out the formulas.
