What is the total surface area of a cone which has a radius of 21 cm and a height of 28 cm? (Take $π =\frac{22}{7}$)

3696 cm2 1848 cm2 5544 cm2 7392 cm2

3696 cm2

We know that, Total surface area of cone = πr (l + r) l2 = r2 + h2 We have, Radius = r = 21 cm Height =  h = 28 cm = l2 = 212 + 282 = l2 = 441 + 784 = l = \(\sqrt {1225}\) = l = 35 Total surface area of cone = \(\frac{22}{7}\) × 21 × (21 + 35) = 22 × 3 × 56 = 3696 cm2