Question

Find the lateral surface area and total surface area of a closed cylindrical tank of diameter 4.2 m and height 4.5 m. Also find the sheet required to make it if 1/12 of sheet actually used was wasted in making process.

Answer 1

r = 2.1
h = 4.5
C.S.A = 2πrh
=2×22/7×2.1×4.5
and TSA = 2πr(r+h)
=2×22/7×(2.1+4.5)
let area of sheet actually used be x
sheet used in process = x - 1/12x =11/12x
11/12x= TSA of tank
so x =TSA × 12/11