the lateral surface area of the figure is 660 sq ft
(but the answer is not matching with the options)
Step-by-step explanation: this figure is called cylinder. the lateral surface area means the area of curved surface.
here the diameter is 10 ft
so radius = diameter/2 = 10/2 ft = 5ft
again, height = 21ft
now the lateral surface area = perimeter of the circular surface X height
= 2X pie X r X h ( here r is the radius and h is height and we will take pie as 22/7)
= 2 X (22/7) X 10 X 21 sq ft
= 2 X 22 X 5 X 3 sq ft
=660 sq ft
( suggest you to recheck the options)