To calculate the area of a rectangle, multiply the length of the rectangle by its width. You need to know the length and width of the rectangle. A ruler, a pen, a paper and a divider are helpful in completing this task.
- Measure the rectangle dimensions
Stretch the divider, and measure the length of the rectangle in question. Use several strokes if the length is bigger than the stretch of the divider. Transfer the divider to the ruler, and read the measurement. Make sure not to tamper with the stretch of the divider during the transfer to avoid an inaccurate measurement. The value you get is the length of the rectangle in question. Use the same procedure to get the value of the width.
- Record the measurement
Using a pen and a paper, record the measurements of the length and the width. You can verify the measurements by repeating the measurement procedure.
- Calculate the area
Multiply the value of the length by the value of the width to get the area of the rectangle. For instance, if the length of the rectangle is 20 centimeters and the width is 12 centimeters, the area of the rectangle is 240 square centimeters.