Area of a Circle Part II

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Area of a Circle Part II

Unit 2 > Lesson 3 of 6

Example 1:	The radius of a circle is 3 inches. What is the area?
Solution:
	= 3.14 · (3 in) · (3 in)
	= 3.14 · (9 in²)
	= 28.26 in²

Example 2:	The diameter of a circle is 8 centimeters. What is the area?
Solution:
	8 cm = 2 ·
	8 cm ÷ 2 =
	= 4 cm

	= 3.14 · (4 cm) · (4 cm)
	= 50.24 cm²

Example 3:	The area of a circle is 78.5 square meters. What is the radius?
Solution:
	78.5 m² = 3.14 · ·
	78.5 m² ÷ 3.14 = ·
	25 m² = ·
	= 5 m

Summary	Given the radius or diameter of a circle, we can find its area. We can also find the radius (and diameter) of a circle given its area. The formulas for the diameter and area of a circle are listed below:

	or