What is the radius of a normal cylinder whose height is 21 cm and curved surface area is 1386 cm2?
Answer & explanation
Correct answer: option 1
We know that,
The curved surface area of the cylinder = C.S.A = 2πrh
We have,
H = 21 cm
C.S.A = 1386 cm2
= 1386 = 2 × \(\frac{22}{7}\) × r × 21
= 1386 = 2 × 22 × 3 × r
= r = 10.5