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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 4 Page 627

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

About 86.5in.^2

Practice makes perfect

We are given a circle with a diameter of 10.5 inches.

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 10.5 inches, the radius of the circle is ( 12* 10.5) inches or 5.25 inches. Let's calculate the area using this information. We can use 3.14 for π.

A = π r^2

r= 5.25

A = π ( 5.25^2)

π ≈ 3.14

A ≈ 3.14 (5.25^2)

Calculate power

A ≈ 3.14 (27.5625)

Multiply

A ≈ 86.54625

Round to 1 decimal place(s)

A ≈ 86.5

We found that A ≈ 86.5, which means that the area of the circle is about 86.5 square inches.

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