Area of a Semi-Circle Calculator

How do you find the area of a semi-circle easily? It is just easy with our area of a semi-circle calculation tool. It is a useful tool to quickly determine the required area based on its radius. Simply enter the radius value into the tool and it will display result.

What is the Area of a Semi-Circle?

The area of a semi-circle is half the area of a full circle. It’s useful in various fields such as geometry, architecture, and engineering. Calculating this area involves using the radius. The radius is the distance from the center of the circle to its edge.

Guide to Use The Tool

To use the calculator, follow these steps:

1. Enter the radius in the input field labeled “Radius (r)”.
2. Click the “Calculate” button.
3. The area will be displayed in the “Area of Semi-Circle” field.

How to Calculate the Area of a Semi-Circle

Formula:

$\text{Area} = \frac{1}{2} \times \pi \times r^2$

Variables:

Variable	Description
$r$	Radius of the semi-circle

Calculation Steps:

1. First, find the radius.

Example:

$r = 5$

2. Next, square the radius.

$r^2 = 5^2 = 25$

3. Now, multiply by π (pi).

$\pi \times 25 \approx 78.54$

4. Finally, divide by 2 to get the semi-circle area.

$\frac{78.54}{2} \approx 39.27$

Input Example

Basic Calculation	Advanced Calculation
Radius (r): 5	Radius (r): 5
Angle (θ): 180	Diameter (d): 10
Area: 39.27	Angle (θ): 180
	Area: 39.27

FAQs

Can I just use the diameter?

Yes, with the advanced mode, you can use the diameter. The calculator will adjust the calculations accordingly.

What if the angle is less than 180 degrees?

If the angle is less than 180°, the calculator will show the area of the sector formed by that angle.

Is π always equal to 3.14?

For simplicity, we use 3.14 for π, but π is an irrational number and its value is approximately 3.14159.