We have,
r = Radius of the region representing Gold score = 10.5 cm
∴ r1 = Radius of the region representing Gold and Red scoring areas = (10.5 + 10.5) cm = 21 cm = 2r cm
r2 = Radius of the region representing Gold, Red and Blue scoring areas = (21 + 10.5) cm = 31.5 cm = 3r cm
r3 = Radius of the region representing Gold, Red, Blue and Black scoring areas = (31.5 + 10.5) cm = 42 cm = 4r cm
r4 = Radius of the region representing Gold, Red, Blue, Black and white scoring areas = (42 + 10.5) cm = 52.5 cm = 5r cm
Now, A, = Area of the region representing Gold scoring area

= 22 × 1.5 × 10.5 = 346.5 cm
2
A
2 = Area of the region representing Red scorring area
= π (2r)
2 - πr
2 = 3πr
2 = 3A
1
= 3 × 346.5 cm
2 = 1039.5 cm
2
A
3 = Area of the region representing Blue scoring area
= π(3r)
2 - π(2r)
2 = 9πr
2 - 4πr
2
= 5πr
2 = 5A
1 = 5 × 346.5 cm
2
= 1732.5 cm
2
A
4 = Area of the region representing black scoring area
= π(4πr)
2 - π(3r)
2 = 7πr
2 = 7A
1
=7 × 346.5 cm
2 = 2425.5 cm
2
A
1 = Area of the region representing white scoring area
= π(5r)
2 - π(4r)
2 - 9πr
2 = 9 A
1
= 9 × 346.5 cm
2 = 3118.5 cm
2