Question

"Question 1 The curved surface area of a right circular cylinder of height 14 cm is 88 cm^2 . Find the diameter of the base of the cylinder. Assume π = 22/7

Class 9 - Math - Surface Areas and Volumes Page 216"

Answer 1

Let r be the radius of the base and h = 14 cm be the height of the cylinder.

Curved surface area of cylinder is given by = 2πrh = 88 cm2

=2 × 22/7 × r × 14 = 88
= r = 88/ (2 × 22/7 × 14)
= r = 1 cm

Thus, the diameter of the base = 2r = 2×1 = 2cm

Answer 2

Right Circular cylinder:

Right circular cylinder is generated by revolution of a rectangular sheet about one of its side so the area of a rectangular sheet gives us the curved surface area of the cylinder and length of the rectangular sheet is equal to the circumference of the circular base.

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Let r be the radius of the base

Given: h = 14 cm be the height of the cylinder.

Curved surface area of cylinder = 2πrh = 88cm²

2πrh= 88

 2 × 22/7 × r × 14 = 88
 

r = 88/ (2 × 22/7 × 14)

 r = 1 cm

Hence, the diameter of the base = 2r = 2×1 = 2cm.

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Hope this will help you...