Question

The area of the ring between two concentric circles is 3168 cm². Find the radii of the two circles if (1) their sum is 42 cm and (2) their difference is 28 cm.​

Answer 1

Step-by-step explanation:

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.