A solid cylinder of base radius 7 cm and height 11 cm is cut horizontally in two equal halves. Find the sum of the total surface areas of the two pieces (in cm2). (if \(\pi=\frac{22}{7}\))
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 1100
A horizontal cut through the middle gives two smaller cylinders, each with the same base radius 7 cm and half the height, \(\frac{11}{2}=5.5\) cm. Each piece has its own curved surface and two circular ends, one of them the new cut face. The total surface area of a cylinder is \(2\pi r(h+r)\).
Total surface area of one piece: \(\displaystyle 2\times\frac{22}{7}\times7\times(5.5+7)=44\times12.5=550\,\mathrm{cm^2}\)
Both pieces together: \(2\times550=1100\,\mathrm{cm^2}\)