If the area of semi-circular region is 77cm 2 , find its perimeter.

The area of the semicircle is, A = πr 2 2 Substitute the values. 77 = 22 7 × r 2 2 ⇒ r 2 = 77 × 7 × 2 22 ⇒ r 2 = 49 ∴ r = 7 cm The perimeter of the semicircle is, P = r ( π + 2 ) Substitute the values P = 7 ( 22 7 + 2 ) ⇒ P = 7 × 36 7 ∴ P = 36 cm Hence, the perimeter of the semicircle is 36 cm

E M B I B E

Understanding ICSE Mathematics Class 9>Chapter 16 - Mensuration>EXERCISE 16.3>Q 3

EASY

9th ICSE

IMPORTANT

Earn 100

Find the perimeter of semi circular plate of radius 3.85cm.

Important Questions on Mensuration

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9th ICSE

IMPORTANT

Understanding ICSE Mathematics Class 9>Chapter 16 - Mensuration>EXERCISE 16.3>Q 4

Find the radius and circumference of a circle whose area is 144

π

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9th ICSE

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Understanding ICSE Mathematics Class 9>Chapter 16 - Mensuration>EXERCISE 16.3>Q 5

A sheet is 11cm long and 2cm wide. Circular pieces 0.5cm. in diameter are cut from it to prepare discs. Calculate the number of disc that can be prepared.

EASY

9th ICSE

IMPORTANT

Understanding ICSE Mathematics Class 9>Chapter 16 - Mensuration>EXERCISE 16.3>Q 6

If the area of semi-circular region is 77cm², find its perimeter.

EASY

9th ICSE

IMPORTANT

Understanding ICSE Mathematics Class 9>Chapter 16 - Mensuration>EXERCISE 16.3>Q 7

In the figure given below, $A C and B D$ are two perpendicular diameters of a circle $A B C D$ . Given that the area of the shaded portion is $308 {cm}^{2}$