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

$\huge\purple{\boxed{\sf AnSwer}}$

Given:-

Radius of outer circle (R)= 56m

Radius of inner circle (r)= 49m

To Find :-

we have to find the difference between the circumference of both circle

Solution:-

Difference between their circumference= C. of outer circle - Circumference of inner circle

$\begin{gathered}\bigstar\tt\ \ Circumference\ of\ circle = 2\pi r \\ \\ \\ :\implies\sf\ Difference \ in\ Circumference= 2\pi R- 2\pi r\\ \\ \\ :\implies\sf\ circumference= 2\pi \big\lgroup R-r\big\rgroup\\ \\ \\ :\implies\sf\ Circumference= 2\times \dfrac{22}{7}\times \big\lgroup 56-49\big\rgroup\\ \\ \\ :\implies\sf\ Circumference= \dfrac{44}{\cancel{7}}\times \cancel{7}\\ \\ \\ \therefore\ \underline{\boxed{\sf\ Difference\ b/w\ their\ circumference= 44m}}\end{gathered}$

Some other important formula:-

$\begin{gathered}\bullet\sf\ Area\ of\ circle= \pi r^2\\ \\ \\ \bullet\sf\ Area\ of\ ring= \pi (R^2-r^2)\end{gathered}$

Answer 2

Answer:

\huge\purple{\boxed{\sf AnSwer}}

AnSwer

Given:-

Radius of outer circle (R)= 56m

Radius of inner circle (r)= 49m

To Find :-

we have to find the difference between the circumference of both circle

Solution:-

Difference between their circumference= C. of outer circle - Circumference of inner circle

\begin{gathered}\begin{gathered}\bigstar\tt\ \ Circumference\ of\ circle = 2\pi r \\ \\ \\ :\implies\sf\ Difference \ in\ Circumference= 2\pi R- 2\pi r\\ \\ \\ :\implies\sf\ circumference= 2\pi \big\lgroup R-r\big\rgroup\\ \\ \\ :\implies\sf\ Circumference= 2\times \dfrac{22}{7}\times \big\lgroup 56-49\big\rgroup\\ \\ \\ :\implies\sf\ Circumference= \dfrac{44}{\cancel{7}}\times \cancel{7}\\ \\ \\ \therefore\ \underline{\boxed{\sf\ Difference\ b/w\ their\ circumference= 44m}}\end{gathered}\end{gathered}

★ Circumference of circle=2πr

:⟹ Difference in Circumference=2πR−2πr

:⟹ circumference=2π

⎩

⎪

⎧

R−r

⎭

⎪

⎫

:⟹ Circumference=2×

7

22

×

⎩

⎪

⎧

56−49

⎭

⎪

⎫

:⟹ Circumference=

7

44

×

7

∴

Difference b/w their circumference=44m

Some other important formula:-

\begin{gathered}\begin{gathered}\bullet\sf\ Area\ of\ circle= \pi r^2\\ \\ \\ \bullet\sf\ Area\ of\ ring= \pi (R^2-r^2)\end{gathered}\end{gathered}

∙ Area of circle=πr

2

∙ Area of ring=π(R

2

−r

2

)