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Step-5

Title: Area of a circle

Grade: 8-a Lesson: S4-L4

Explanation: Let us verify the answer here with the steps.

Description:

Step	Type	Explanation	Answer
1	Problem	A circular garden with a diameter of 24 centimeters is surrounded by a walkway of width 4 centimeters. Find the area of the walkway.
2	Hint	Formula used	\$"Area" = \pi \times r^2\$
3	Step	The walkway is enclosed between a	smaller circle of radius = 12 cm and a larger circle of radius = 16 cm
4	Step	The area of the walkway =	the area enclosed by the larger circle - the area enclosed by the smaller circle
5	Step	Therefore, The area of the walkway =	\$π \times 16 \times 16 - π \times 12 \times 12\$ ⇒ \$256 \times π - 144 \times π\$ ⇒ \$112π cm²\$ ⇒ \$112 \times (3.14)\$ = 351.68 cm²
6	Step	Hence, the area of the walkway is	351.68 cm²

Step

Type

Explanation

Answer

Problem

A circular garden with a diameter of 24 centimeters is surrounded by a walkway of width 4 centimeters. Find the area of the walkway.

Hint

Formula used

\$"Area" = \pi \times r^2\$

Step

The walkway is enclosed between a

smaller circle of radius = 12 cm and a

larger circle of radius = 16 cm

Step

The area of the walkway =

the area enclosed by the larger circle - the area enclosed by the smaller circle

Step

Therefore, The area of the walkway =

\$π \times 16 \times 16 - π \times 12 \times 12\$

⇒ \$256 \times π - 144 \times π\$

⇒ \$112π cm²\$

⇒ \$112 \times (3.14)\$ = 351.68 cm²

Step

Hence, the area of the walkway is

351.68 cm²