IXL - Circles: word problems (Geometry practice)

After stepping into a room with unusual lighting, Audrey's pupil has a radius of 3 millimeters. What is the pupil's circumference?

If necessary, round your answer to the nearest hundredth.

millimeters

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Learn with an example

question

Miranda's drink coaster has a radius of 3 centimeters. What is the coaster's area?

If necessary, round your answer to the nearest hundredth.

square centimeters

key idea

Use this formula to find the area from the radius.

A = 𝜋 × r²

Use 3.14 as an approximation for 𝜋.

𝜋 ≈ 3.14

solution

The radius is 3 centimeters. Replace r by 3 in the formula.

A	=	𝜋 × r²

	≈	3.14 × 3²

	≈	3.14 × 3 × 3

	≈	28.26

The area is about 28.26 square centimeters.

Looking for more? Try these:

Lesson: Area of circles

Lesson: Circumference of circles

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Not feeling ready yet? These can help:

S.9Area and circumference of circles

Lesson: Area of circles

Lesson: Circumference of circles

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