Answer:
The amount of steel used = 94.38 
Step-by-step explanation:
Height of the tank = 4.5 m.
Diameter of the tank = 4.2 m.
But,
radius = 
= 
radius = 2.1 m
Total surface area of a cylinder = 2
rh + 2

= 2
r(r + h)
= 2 x
x 2.1 (2.1 + 4.5)
= 44 x 0.3 (6.6)
= 87.12
Total surface area of a cylinder = 87.12 
Since
of the steel was wasted, then;
x 87.12 = 7.26 
Actual area of steel sheet used = 87.12 + 7.26
= 94.38 
Thus, 94.38
of steel was used in making the tank.