Question

The areas of two concentric circles is 154 cm2 and 616 cm respectively. Find ine width of the gap between the two circles shown by the shaded portion in the adjacent figure Hint: Find the radius of the two circles and subtract).​

Answer 1

The width of the ring is equal to the difference between the radius of the outer circle and the radius of the inner circle

Let the radius of the outer circle be R and that of the inner circle be r

Given that the area of outer circle is 616 cm2

∴ πR^2=616 cm2

⇒R^2  =22616×7=196 cm^2

∴R=14 cm

Also, the area of the inner circle is 154 cm2

∴ πr^2=154 cm2

⇒r^2=22154×7=49 cm2

∴r=7 cm.

∴  The required answer ⇒ R – r = 14−7 = 7 cm.

Hence, the width of the ring is 7 cm

Hope this helps you! Please mark my answer as the Brainliest! Have a good  day!