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Geometry worked example

Calculate the area of a circle with radius 7

Apply A = πr² to a circle with radius 7 and find both the exact and approximate area.

Question

What is the area of a circle with radius 7?

Step-by-step solution

The area of a circle depends on its radius. Use A = πr², where r is the distance from the center to the edge.

Step 1: Substitute the radius

Here r = 7, so A = π(7)².

Step 2: Square and simplify

7² = 49, giving A = 49π square units. This is the exact answer.

Step 3: Approximate if needed

Using π ≈ 3.14159, 49π ≈ 153.94 square units.

If the radius is measured in centimeters, the area is 49π cm², or approximately 153.94 cm². Remember to square the length unit when reporting area.