(i) Petrol tank is in the form of cylinder.
Diameter, d = 4.2 m
h = 4.5 m
TSA of petrol tank = 2πr(r + h)
= 44 × 0.3 × 6.6
= 87.12 m2
(ii) ∴ Area of iron required for manufacturing tanker = 87.12 m2 .
If iron used is 1 sq. m then there is a loss of \(\frac{1}{12}\).
Iron required except loss = 1 - \(\frac{1}{12}\)
= \(\frac{11}{12}\)m2
Area of \(\frac{11}{12}\)m2 is 87.12 m2 .
Area of 1 m2 … ? …
= 1 x 87.12 x \(\frac{12}{11}\)
= 95.04 m2 .