Question

a cyclindrical pillar is 28cm in diameter and 3m height. what is its curved surface area

Answer 1

Given : -
Diameter = 28cm
height = 3m = 300cm

radius = diameter/2
radius = 28/2 = 14cm

C.S.A = 2πrh
= 2*22/7*14*300
= 26400

C.S.A = 26400cm sq. = 2.64m sq.

Answer 2

$2\pi \times r \times h \\ 2 \times \frac{22}{7} \times \frac{28}{2} \times 300 = 26400 {cm}^{2}$