Radius of a cylinder is 7 cm and height is 10 cm. Find the curved surface area.

Explanation

• Curved surface area of a cylinder = 2πrh = 2 × (22/7) × 7 × 10 = 440 cm².
• The 7 in the radius cancels the 7 in 22/7, which is why exam setters choose a radius of 7 or 14.
• Curved surface area covers only the side of the cylinder, so the two circular ends are left out.
• Add the two ends and you get the total surface area: 2πrh + 2πr² = 440 + 308 = 748 cm².
• The answer must be in square centimetres, because surface area is a two-dimensional measure.