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Glencoe Math: Course 2, Volume 2

GM

Glencoe Math: Course 2, Volume 2 View details

2. Area of Circles

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Exercise 21 Page 629

The area of a circle equals the product of π and the square of its radius.

About 124.6cm^2

Practice makes perfect

Let's consider the given circle.

Circle

We want to find the area of the circle. Recall that the area A of a circle equals the product of π and the square of its radius r. A = π r^2 Since the diameter of the circle is 12.6 meters, the radius of the circle is ( 12* 12.6) centimeters or 6.3 centimeters. Let's calculate the area using this information. We can use 3.14 for π.

A = π r^2

r= 6.3

A = π ( 6.3^2)

π ≈ 3.14

A ≈ 3.14 (6.3^2)

Calculate power

A ≈ 3.14 (39.69)

Multiply

A ≈ 124.6266

Round to 1 decimal place(s)

A ≈ 124.6

We found that A ≈ 124.6, which means that the area of the circle is about 124.6 square centimeters.

Subchapter links

Guided Practice p.626

Independent Practice p.627-628

H.O.T. Problems p.628

Standardized Test Practice p.628-630

Extra Practice p.629

Common Core Review p.630