Question

the area of the ring between to concentric circles is 3168cm². Find the radii of two circles if i) the sum is 42 cm​

Answer 1

Answer:

Let two radius are 'x' and 'y', so,

x+y=42...(1)

and

x−y=28...(2)

Now adding (1) and (2), we get

2x=70

x=35

Putting in (1)

35+y=42

y=7

Therefore, radius of two concentric circles are 35 cm and 7 cm.