A garden roller is 1 $m$ long and 84 cm in diameter. It makes 500 complete revolutions to level a lawn exactly once. Find the area of the lawn in $m^2$. Take π = 22/7.

In one revolution the roller unrolls its curved surface onto the ground, a strip as wide as the roller is long and as long as its circumference: π$d=(22/7)\times 0.84=2.64$ m. So one revolution covers $2.64\times 1=2.64{\text{m}}^2$, and 500 of them cover $1320{\text{m}}^2.(2.64{\text{m}}^2$ is a single revolution; using the radius 0.42 m in place of the diameter halves every strip and gives $660{\text{m}}^2$; taking the circumference as 2π$d$ doubles it to $2640{\text{m}}^2.$)