Question

PQRS is the diameter of a circle of radius 6 cm. The lengths PO, OR and RS a
equal, Semi-circles are drawn with PO and OS as diameters as shown in figure
Find the ratio of the area of the shaded region to that of the unshaded region,​

Answer 1

Answer:

The ratio of area of shaded region to that of the unshaded region

= (area of bigger semicircle-area of smaller semicircle) / (area of bigger semicircle+area of smaller semicircle)

=

2

πR

2

+

2

πr

2

2

πR

2

−

2

πr

2

=

R

2

+r

2

R

2

−r

2

=

(2r)

2

+r

2

(2r)

2

−r

2

=

5

3