Content

• To step
• Tips
• Warnings

A semicircle is half of a circle. Therefore, by finding the area of ​​a full circle and then dividing it by two, you can find the area of ​​a semicircle. If you want to know how to quickly find the area of ​​a semicircle, read on to Step 1 to get started.

To step

1. Determine the radius (radius) of the semicircle. You need the radius to find the area of ​​a semicircle. Suppose the radius is 5 cm.
   • If only the diameter is given, divide it by 2 to get the radius. For example, if the diameter of the circle is 10 cm, divide it by 2 (10/2) to calculate that the radius is 5 cm.
2. Calculate the area of ​​the full circle and divide it by 2. The formula for determining the area of ​​a full circle is πr, where "r" is the radius or radius of the circle. To find the area of ​​the semicircle, divide the entire area by 2, indicated in the formula πr / 2. Enter "5 cm" in the formula for the answer. You can approximate pi with your calculator, hold 3.14 for π, or just leave the symbol. Here's how to do that:
   • Area = (πr) / 2
   • Area = (π x 5 cm x 5 cm) / 2
   • Area = (π x 25 cm) / 2
   • Area = (3.14 x 25 cm) / 2
   • Area = 39.25 cm
3. Give your answer as square meter or centimeter. Because you are determining the area of ​​a shape, use area units (such as cm) in your answer to indicate that it is a two-dimensional object. When you calculate the volume of an object, you are working with cubic units (such as cm).

Tips

• The area of ​​a circle is (pi) (r ^ 2)
• The area of ​​a semicircle is (1/2) (pi) (r ^ 2).

Warnings

• You must use the radius, not the diameter, to calculate the area. If the diameter is given, divide it by 2 to get the radius.