Question

A roller 2m long and 0.7m in diameter makes 60 revolution in a minutes on a road. How much area rolled by it?

Answer 1

$tsa \: of \: roller = 2\pi \: \times \: r(r+h)$
$= 2 \times \frac{22}{7} \times \frac{0.7}{2} ( \frac{0.7}{2} + 2) \\ \\ = \frac{30.8}{12} ( \frac{0.7 + 4}{2} ) \\ \\ = \frac{30.8}{12} \times \frac{4.7}{2} \\ \\ = \frac{144.76}{24} = \frac{14476}{100} \times \frac{1}{24}$