Question

The radius of the inner circle and the outer circle as given in the figure is 49m and 56m
respectively. Find the difference of the circumference of both the circles.​
​

Answer 1

Answer:

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$\bf\underline{\underline{Given}}$

• Radius of inner circle = 49m
• Radius of outer circle = 56m

RTF = the difference of the circumference of both the circles.

CIRCUMFERENCE OF INNER CIRCLE ↓

circumference of inner circle = 2πr

= 2 × π × 49m [take π as $\frac{22}{7}$

= 2 × $\frac{22}{7}$ × 49m

$= 2 \times \frac{22}{\cancel7} \times \cancel49m \\ = 2 \times 22 \times 7 \\ = 308{m}^{2} - - - - (i)$

CIRCUMFERENCE OF OUTER CIRCLE

circumference of outer circle = 2πr

= 2 × π × 49m [take π as $\frac{22}{7}$

= 2 × $\frac{22}{7}$ × 56m

$= 2 \times \frac{22}{7} \times 56m \\ = 2 \times \frac{22}{ \cancel7} \times \cancel56m \\ = 2 \times 22 \times 8 \\ = {352}^{2} - - - - (ii)$

now to find the difference ↓

subtract ( i ) from ( ii )

= 352m² - 308m²

= 44 m

therefore 44m is the difference between these two circles