If you’re working on a project involving semicircles whether it’s for school, design, or construction knowing how to calculate the area is important. A semicircle is simply half of a circle, so its area is half the area of a full circle.
What Is a Semicircle?
A semicircle is formed when a circle is divided into two equal halves. It has one straight edge (the diameter) and one curved edge (the arc).
The Formula for the Area of a Semicircle
To find the area of a semicircle, use this formula:
Area = (1/2) × π × r²
- r = radius of the semicircle
- π (pi) ≈ 3.14
If you only know the diameter (d), remember the radius is half of it:
r = d ÷ 2
So the formula using diameter becomes:
Area = (π × d²) ÷ 8
Example Calculation
Let’s say your semicircle has a radius of 5 inches:
- Area = (1/2) × 3.14 × 5 × 5
- Area = 0.5 × 3.14 × 25
- Area = 39.25 square inches
Calculating manually is easy, but using a calculator saves time and ensures accuracy. Just enter your radius or diameter, and get the exact area instantly. It’s perfect for students, engineers, and anyone working with semicircular shapes.