Question

ad is the diameter of a circle of 6 cm and ab = bc =cd. semi circles are drawn with ab and bd are diameters as shown in the figure. find the perimetre and area of the shaded region.

Answer 1

perimeter = 2*22/7*r
22/7 *d
area = 22/7*r^2



perimeter of large circle( 1/2)= 2*22/7* 3 *1/2
=9.4cm
1/2 perimeter of medium circle =1/2 *22/7*4
= 6.2cm
1/2 perimeter of smallest circle = 1/2 *22/7*2
=3.1cm
perimeter of shaded area is = 9.4+6.2+3.1
= 18.7 cm

area of 1/2 of large circle = 1/2*22/7*3*3
=14.1cm^2
area of 1/2 medium circle =1/2 *22/7*2*2
= 6.2cm^2
area of 1/2 small circle = 1/2 *22/7*1*1
=1.5cm^2
the area of shaded area = (14.1 -6.2) +1.5
= 9.4 cm^2