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McGraw Hill Integrated II, 2012

MH

McGraw Hill Integrated II, 2012 View details

9. Areas of Circles and Sectors

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Exercise 1 Page 786

Recall the formula for finding the area of a circle.

1385.4yd^2

Practice makes perfect

The area of a circle with radius r is calculated using the formula below. A=π r^2 From the figure, we know that the radius of the circle is 21yd. By substituting 21 for r in the formula, we can calculate A.

A=π r^2

r= 21

A=π( 21)^2

Calculate power

A=π(441)

Use a calculator

A=1385.442360...

Round to 1 decimal place(s)

A≈ 1385.4

The area of the circle is approximately 1385.4 square yards.

Subchapter links

Exercises p.786-790