Question

. In a hollow cylinder, the radius of the bigger circle is 21 cm and the radius of the smaller circle is 14 cm. Find the area of the ring. (Take π = 22/7) *

Answer 1

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Answer 2

$\sf\red{\underline{\underline{Answer:}}}$

$\sf{The \ area \ of \ ring \ is \ 770 \ cm^{2}}$

$\sf\orange{Given:}$

$\sf{In \ a \ hollow \ cone,}$

$\sf{\implies{Radius \ of \ bigger \ circle(r1)=21 \ cm}}$

$\sf{\implies{Radius \ of \ smaller \ circle(r2)=14 \ cm}}$

$\sf\pink{To \ find:}$

$\sf{The \ area \ of \ the \ ring.}$

$\sf\green{\underline{\underline{Solution:}}}$

$\boxed{\sf{Area \ of \ circle=\pi\times \ r^{2}}}$

$\sf{\therefore{Area \ of \ ring=\pi\times \ r1^{2}-\pi\times \ r2^{2}}}$

$\sf{\therefore{Area \ of \ ring=\frac{22}{7}\times({21}^{2}-14^{2})}}$

$\sf{\therefore{Area \ of \ ring=\frac{22}{7}\times(21+14)(21-14)}}$

$\sf{\therefore{Area \ of \ ring=\frac{22}{7}\times35\times7}}$

$\sf{\therefore{Area \ of \ ring=22\times35}}$

$\sf{\therefore{Area \ of \ ring=770 \ cm^{2}}}$

$\sf\purple{\tt{\therefore{The \ area \ of \ ring \ is \ 770 \ cm^{2}}}}$