PSLE
The figure shows a rectangular grass patch and an L-shaped footpath. The width of the footpath is 40 cm. The footpath is tiled using 64 circular tiles of diameter 20 cm, following the pattern shown. Each tile is in contact with those next to it.

1. What is the area of the footpath not covered by the tiles? Take π = 3.14.
2. What is the perimeter of the grass patch?

(a)
Area of a circular tile
= 3.14 x 10 x 10
= 314 cm²

Area of a square plot that is under a circular tile
= 20 x 20
= 400 cm²

Area of the footpath not covered by a circular tile
= 400 - 314
= 86 cm²

Area of the footpath not covered by all the tiles
= 86 x 64
= 5504 cm²

(b)
Number of circular tiles touching the 2 lengths of the grass patch
= (64 - 4) ÷ 2
= 60 ÷ 2
= 30

Perimeter of the grass patch
= 2 x 30 x 20
= 1200 cm

Answer(s): (a) 5504 cm²; (b) 1200 cm