Different formulas exist for finding the areas of different types of polygons. To find the area of any polygon, first identify which formula to use and then replace the variables with the known dimensions of the polygon.
- Determine the formula for your polygon
The formula to find the area of four-sided polygons like squares, rectangles and rhombuses is the length times the width, or L x W. The formula to find the area of a triangle is the length of the base times 1/2 the height, or B x 1/2 H.
- Find the values for the variables in the formula
Look at the item for which you are calculating the area. If the values are listed, plug them into the formula. If the values are not known, such as those for a room, measure the sides of the object or space.
- Calculate the area
After replacing the variables with numerical values, check to ensure that the units of measurement are the same. If the length is measured in feet and the height is in inches, convert the length to the equivalent number of inches. When you perform the needed calculations, remember the order of operations: parentheses followed by exponents, then division and multiplication, and finishing with addition and subtraction. Make sure your final answer is in units squared.