# Diameter of a Semicircle

## Method #1 – Diameter from the Area

### Formula – How to calculate the diameter of a semicircle from the area

π is approximately equal to 3.1415926535

Step 1: Find the radius

Radius = √(2 x Area ÷ π)

Step 2: Find the diameter

Diameter = Radius x 2

##### Example

A semicircle has an area of 300

Radius = √(2 x 300 ÷ π)

Radius = √(2 x 300 ÷ 3.14159)

Diameter = 13.8198 x 2

Diameter = 27.6396

## Method #2 – Diameter from the Circumference

### Formula – How to calculate the diameter of a semicircle from the circumference

π is approximately equal to 3.1415926535

Step 1: Find the Radius

Radius = Circumference ÷ π

Step 2: Find the Diameter

Diameter = Radius x 2

##### Example

A semicircle has a circumference of 35

Radius = 35 ÷ π = 35 ÷ 3.14159 = 11.14086

Diameter = 11.14086 x 2 = 22.28172

## Method #3 – Diameter from the Radius

### Formula – How to calculate the diameter of a semicircle from the radius

Diameter = Radius x 2

##### Example

A semicircle has a radius of 10

Diameter = 10 x 2 = 20