To calculate the area of an ellipse, multiply the major radius by the minor radius, then multiply by pi. For simplicity, use a commonly accepted approximation of pi, such as 3.142.
If the lengths of the major and minor radii are not labelled, they can be identified visually. Look at an ellipse to identify the shortest possible line that divides the ellipse in half. This is the minor radius. Now, look for the longest possible radius, which is also called the major radius.
To illustrate the calculations with a hypothetical example, consider an ellipse that is 6 centimeters long and 7 centimeters high. The area approximately equals 6 times 7 times 3.142, or about 132 square centimeters.