PSLE The figure shows 6 circles, each of radius 14 cm. Each circle touches the circles next to it.
(Take π =
227)
- Find the perimeter of the shaded part.
- Find the area of the shaded part.
(a)
Diameter of each circle
= 2 x 14
= 28 cm
Perimeter of the shaded part
= Circumference of 3 circles
= 3 x
227 x 28
= 264 cm
(b)
Length of the dotted rectangle
= 4 x 14
= 56 cm
Breadth of the dotted rectangle
= 2 x 14
= 28 cm
Area of the dotted rectangle
= 56 x 28
= 1568 cm
2 Area of 2 semicircles
= Area of 1 circle
=
227 x 14 x 14
= 616 cm
2 Area of the shaded part
= 1568 + 616
= 2184 cm
2 Answer(s): (a) 264 cm; (b) 2184 cm
2