Area of a Circle Calculator

This Area of a Circle Calculator helps you find the space inside a circle when the radius is known. It uses the formula \(A = \pi r^{2}\), where \(r\) is the radius and the answer is written in square units. First square the radius, then multiply by \(\pi\) to get the area. It is a simple way to check answers, understand the circle area formula, and practise basic geometry step by step.

In the diagram, the radius is labeled \(r\).

Step-by-step method

1. Identify what is given.
2. Write the formula.
3. Substitute the value and calculate the area.

Formula:

Example 1:

Step 1 - Identify what is given.

In this problem: The given radius is \(r = 5\).

Step 2 - Write the formula.

In this problem: Use the circle area formula: \(A = \pi r^{2}\).

Step 3 - Substitute the value and calculate the area.

In this problem: Substitute \(r = 5\): \(A = \pi \times 5^{2} = 78.53981634\).

Final answer:

Example 2:

Step 1 - Identify what is given.

In this problem: The given radius is \(r = 3.5\).

Step 2 - Write the formula.

In this problem: Use the circle area formula: \(A = \pi r^{2}\).

Step 3 - Substitute the value and calculate the area.

In this problem: Substitute \(r = 3.5\): \(A = \pi \times 3.5^{2} = 38.48451001\).

Final answer: