How much iron sheet (in m2) will be needed to construct a rectangular tank measuring 12 m × 9 m × 6 m, if a circular opening of radius 1.4 meters is to be left at the top of the tank?
Show answer & explanation
Correct answer: B
Explanation
Total surface area of the cuboid = 2(lb + bh + hl)
= 2(12 × 9 + 9 × 6 + 12 × 6)
= 2(108 + 54 + 72)
= 468 m²
Area of the circular hole left at the top = πr²
= 22/7 × 1.4 × 1.4
= 6.16 m²
Iron sheet required = 468 − 6.16
= 461.84 m²