PSLE
The figure shows a rectangular grass patch and an L-shaped footpath. The width of the footpath is 16 cm. The footpath is tiled using 64 circular tiles of diameter 8 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 4 x 4
= 50.24 cm²

Area of a square plot that is under a circular tile
= 8 x 8
= 64 cm²

Area of the footpath not covered by a circular tile
= 64 - 50.24
= 13.76 cm²

Area of the footpath not covered by all the tiles
= 13.76 x 64
= 880.64 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 8
= 480 cm

Answer(s): (a) 880.64 cm²; (b) 480 cm