Library
Mathematics

Understanding the Area of a Circle

This lesson explores the geometric meaning of the area of a circle and demonstrates how to calculate it using the radius.

Scene 1 of 4
What is Circle Area?
Circle with Radius 77 cm
r=7 cmr = 7 \text{ cm}
Imagine a circle with a radius of seven centimetres. How much space is trapped inside its boundary?
Step-by-step solver
1

(Solution) State Formula

Identify the standard formula for the area of a circle.

A=πr2A = \pi r^2
2

(Solution) Substitute

Plug the given radius value of 7 into the formula.

A=π×72A = \pi \times 7^2
3

(Solution) Square the radius

Calculate the value of the radius squared.

72=497^2 = 49
4

(Solution) Final Answer

Combine the result with pi to state the area.

A=49π cm2A = 49\pi \text{ cm}^2

Original question

A circle has radius 7 cm. Calculate its area, leaving your answer in terms of pi.

Follow-up chat

Ask me anything about this lesson — I'll answer using what we just covered.