SaiBook.us WordProblems

Home Course Section

Register Enroll Refer

Step-3

Title: Circumference of a circle

Grade: 8-a Lesson: S4-L3

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

Description:

Step	Type	Explanation	Answer
1	Problem	The area of a circle is 144π square units. What is the circumference of the circle?
2	Hint	Formula used	\$"Area" = \pi \times r^2\$ \$"Circumference" = 2\pi r\$
3	Step	Area of the circle	144π square units
4	Step	Substitute the value of area in \$"Area" = \pi \times r^2\$	\$"144π" = \pi \times r^2\$ ⇒ \$"144π" = \pi \times r^2\$ ⇒ \$"144" = r^2\$ ⇒ \$r = 12\$
5	Step	Substitute the value of 'r' in \$"Circumference" = 2\pi r\$	\$"Circumference" = 2\pi r\$ ⇒ C = 2 x 3.14 x 12 ⇒ C = 75.36
6	Step	Hence, the circumference of the circle	75.36 units

Step

Type

Explanation

Answer

Problem

The area of a circle is 144π square units. What is the circumference of the circle?

Hint

Formula used

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

Step

Area of the circle

144π square units

Step

Substitute the value of area in \$"Area" = \pi \times r^2\$

\$"144π" = \pi \times r^2\$

⇒ \$"144π" = \pi \times r^2\$

⇒ \$"144" = r^2\$

⇒ \$r = 12\$

Step

Substitute the value of 'r' in \$"Circumference" = 2\pi r\$

\$"Circumference" = 2\pi r\$

⇒ C = 2 x 3.14 x 12

⇒ C = 75.36

Step

Hence, the circumference of the circle

75.36 units