A semicircle corresponds to the exact half of a circle. To calculate the area of a semicircle, you will simply need to calculate the area of the corresponding circle and divide it by two. This tutorial shows the steps to calculate the area of a semicircle.
Steps
Step 1. Identify the radius of the semicircle
To locate the area of a semicircle you need to know its radius. Let's assume that the radius of our example measures 5 cm.
If you are only given the diameter measurement, to get the radius, simply divide it by two. For example, if the given diameter is 10 cm, the radius will be 10/2 = 5 cm
Step 2. The area of a semicircle corresponds exactly to half the area of the corresponding circle
The formula for calculating the area of a circle is as follows πr2, where is it r represents the measure of the circle radius. Since you are calculating the area of a semicircle, you will only need 'half' of the area of the corresponding circle. This means that you will have to use the formula to calculate the area of a circle and divide the result by two. So the correct formula to use in our case is the following πr2/2. Now you just have to replace the known values, that is the radius equal to 5 cm. In the case of the constant π you can use the approximate value of 3.14, the value provided by your calculator or leave the symbol π. At the end you will get:
- Area = (πr2)/2
- Area = (π x 5cm x 5cm) / 2
- Area = (π x 25 cm2)/2
- Area = (3.14 x 25 cm2)/2
- Area = 39.25 cm2
Step 3. Remember to express your result in square units, in our case square centimeters, as you are calculating the area enclosed by a geometric figure
This indicates that you are working with a two-dimensional object. If you were calculating the volume instead, use cubic units of measure, such as cm3.
Advice
- The formula for calculating the area of a circle is (π * r2).
- The formula for calculating the area of a semicircle is (π * r2)/2.
