The given figure consists of four small semicircles and two big semicircles.  If the smaller semicircles are equal in radii and the bigger semicircles are also equal in radii, find the perimeter and the area of the shaded portion of the figure.  Given that radius of each bigger semicircle is 42cm. (Ans:528cm, 5544 sq cm)

Ans:    Perimeter of the shaded region

= 2 [ Perimeter (Bigger semi circle) + Perimeter (smaller semi circle ) + Perimeter (small semi circle )]

= 2 ( 42 Π + 21 Π + 21 Π )

= 84 Π

=2 x 84 x22/7  = 24 x 22 = 528 cm

Area of shaded region

= [ Area(big semi circle )]

= 2 x Π x 42 x 42 x 1/2  =22/7 x 42 x 42 = 5544 cm²