Radius of the roller (r) = 84/ 2 cm = 42 cm

Length of the roller (h) = 120 cm

Curved surface area of the roller = 2πrh

= 2 × 22/ 7 × 42 × 120 cm^{2} = 44 × 720 cm^{2} = 31680 cm^{2}

∴ area covered by the roller in 1 revolution = 31680 cm^{2}

∴ area covered by the roller in 500 revolutions = 31680 × 500 cm^{2} = 15840000 cm

Hence, area of the playground = 15840000/ 100× 100 m^{2} **= 1584 m**^{2} Ans.