SaiBook.us WordProblems

Home Course Section

Register Enroll Refer

Step-4

Title: Semi-circles

Grade: 8-a Lesson: S4-L5

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

Description:

Step	Type	Explanation	Answer
1	Problem	The perimeter of a semi-circle is 30 cm. What is the diameter of the semi-circle? (Use π = 3.14)
2	Hint	Formula used	\$"Perimeter" = πr + 2r\$
3	Step	Given that, The perimeter of a semi-circle is	30cm
4	Hint	We know that, the perimeter of a semi-circle	= πr + 2r
5	Step	Therefore,	30 = πr + 2r ⇒ \$30 = (π + 2)r\$ ⇒ \$30 = (3.14 + 2)r\$ ⇒ \$30 = 5.14 \times r\$ ⇒ \$(30)/(5.14) = r\$ ⇒ \$(30)/(5.14) = r\$ ⇒ \$5.83 = r\$
6	Hint	We know that,	The diameter (d) = 2r ⇒ \$d = 2 \times 5.83\$ ⇒ \$d = 11.67\$
7	Step	Therefore, the diameter of a semi-circle is	11.67 cm.

Step

Type

Explanation

Answer

Problem

The perimeter of a semi-circle is 30 cm. What is the diameter of the semi-circle? (Use π = 3.14)

Hint

Formula used

\$"Perimeter" = πr + 2r\$

Step

Given that,

The perimeter of a semi-circle is

30cm

Hint

We know that, the perimeter of a semi-circle

= πr + 2r

Step

Therefore,

30 = πr + 2r

⇒ \$30 = (π + 2)r\$

⇒ \$30 = (3.14 + 2)r\$

⇒ \$30 = 5.14 \times r\$

⇒ \$(30)/(5.14) = r\$

⇒ \$5.83 = r\$

Hint

We know that,

The diameter (d) = 2r

⇒ \$d = 2 \times 5.83\$

⇒ \$d = 11.67\$

Step

Therefore, the diameter of a semi-circle is

11.67 cm.