 # Find Circumferences and Areas of Circles Using a Calculator

In this worksheet, students find the circumferences and areas of circles given their radii. They use a calculator to work out their answers. Key stage:  KS 3

Curriculum topic:   Number

Curriculum subtopic:   Use Calculators/Technology for Accuracy

Difficulty level:   ### QUESTION 1 of 10

This worksheet is about finding the circumferences and areas of circles using a calculator.

You must learn these two important formulae for a circle of radius, r :

Circumference of a circle = 2 π r

Area of a circle = π r2

Examples

Find the circumference and area of a circle of radius 6 cm.

Circumference = 2 π r = 2 x π x 6 = 12 x π = 37.7 cm  (1 dp)

Area = π r2 =  π x 62 = π x 36 = 113.1 cm2  (1 dp)

Find the circumference of a circle of radius 25 cm.

(Just write the number to 1 decimal place)

Find the circumference of a circle of radius 26 cm.

(Just write the number to 1 decimal place)

Find the circumference of a circle of radius 71 cm.

(Just write the number to 1 decimal place)

Find the circumference of a circle of radius 16 cm.

(Just write the number to 1 decimal place)

Find the circumference of a circle of radius 57 cm.

(Just write the number to 1 decimal place)

Find the area of a circle of radius 41 cm.

(Just write the number to the nearest whole number)

Find the area of a circle of radius 31 cm.

(Just write the number to the nearest whole number)

Find the area of a circle of radius 4 cm.

(Just write the number to the nearest whole number)

Find the area of a circle of radius 43 cm.

(Just write the number to the nearest whole number)

Find the area of a circle of radius 13 cm.

(Just write the number to the nearest whole number)

• Question 1

Find the circumference of a circle of radius 25 cm.

(Just write the number to 1 decimal place)

157.1
• Question 2

Find the circumference of a circle of radius 26 cm.

(Just write the number to 1 decimal place)

163.4
• Question 3

Find the circumference of a circle of radius 71 cm.

(Just write the number to 1 decimal place)

446.1
• Question 4

Find the circumference of a circle of radius 16 cm.

(Just write the number to 1 decimal place)

100.5
• Question 5

Find the circumference of a circle of radius 57 cm.

(Just write the number to 1 decimal place)

358.1
• Question 6

Find the area of a circle of radius 41 cm.

(Just write the number to the nearest whole number)

5281
• Question 7

Find the area of a circle of radius 31 cm.

(Just write the number to the nearest whole number)

3019
• Question 8

Find the area of a circle of radius 4 cm.

(Just write the number to the nearest whole number)

50
• Question 9

Find the area of a circle of radius 43 cm.

(Just write the number to the nearest whole number)

5809
• Question 10

Find the area of a circle of radius 13 cm.

(Just write the number to the nearest whole number)

531
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