Question

The height of a right circular cylinder with lateral surface area 792 sq cm is 21. The diameter of the base is:
(A) 3 cm (B) 6 cm (C) 12 cm (D) 24 cm

Answer 1

d=2r
2×22/7×r=792
22/7×21×d=792
66d=792
d=12
(c)

Answer 2

Heya dear user !!!

Here is your answer,

==============================

Given :-
height of the cylinder = 21cm
Lateral surface area = 792cm²

We know that,
Lateral surface area of cylinder = 2πrh in which 'r' is radius and 'h' is height.

=> Lateral surface area of cylinder = 792

=> 2πrh = 792

=> 2×22/7× r ×21 = 792

=> 132×r = 792

=> r = 792/132

=> r = 6

radius (r) = 6 cm

Diameter = 2r = 2×radius = 2×6 = 12cm

==============================

So, correct option is (c)12cm

==============================

Hope it helps.