How to find the Area of a Circle

 

In order to find the area of a circle you use the formula : Area equals pi times radius squared.

• π = Is an irrational number calculated by dividing the circumference of a circle by it's diameter which equals 3.14159 ........
• Radius = distance from the center to the edge of the circle.
• Diameter = distance all the way across the circle.
• If you know the diameter, divide by 2 to find the radius.

Example 1: Radius Given

• Radius = 6 cm
• Use π ≈ 3.14
• Calculate: 3.14 × 6²
• Answer ≈ 113.04 cm²

Example 2: Diameter Given

• Diameter = 24 cm
• Radius = 24 ÷ 2 = 12 cm
• Calculate: 3.14 × 12²
• Answer ≈ 452.16 cm²

Key Points

• Use the radius in the formula.
• Divide the diameter by 2 to find the radius.
• π is an irrational number, so answers are often approximations.
• Area is always written in square units (cm², m², etc.).

Quick Review

✅ Area = space inside a circle
✅ Formula: A = πr²
✅ Radius = center to edge
✅ Diameter = across the circle
✅ Area is always measured in square units (cm²)

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