Question

13. There is a circular flower bed of radius 30 m. There is a 10 m wide running
track around it What is the area of the running track?
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Answer 1

Answer

$\:\:$

Given

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• Radius of circular flower bed = 30m

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• Width of running track = 10m

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Find

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• Area of the running track

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$\underline{\bold{\texttt{Area of circle :}}}$

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$\bf \dag \ \ \pi \times r^2$

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⥤ Area of running track = Area of Circle with radius 40m - Area of circle with radius 30m

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⟾ Area of track = $\sf \pi \times 40^2 - \pi\times 30^2$

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⟾ Area of track = $\sf \pi ( 40 ^2 - 30 ^2 )$

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⟾ Area of track = $\sf \pi ( 1600 - 900 )$

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⟾ Area of track = $\sf \pi ( 700 )$

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⟾ Area of track = $\sf \dfrac { 22 } { 7 } \times 700$

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⟾ Area of track = $\sf 22 \times 100$

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⟾ Area of track = $\bf 2200 sq. m$

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Hence the area of running track would be 2200 sq. m

Answer 2

ɢɪᴠᴇɴ :-

• Radius of circular flower bed i.e 30m
• Width of running track i.e. 10m

ᴛᴏ ꜰɪɴᴅ :-

• Area of the running track.

ꜱᴏʟᴜᴛɪᴏɴ :-

we know,

$\large{\boxed{\pink{\sf{Area \: = \pi r^2}}}}$

{Area of running track = Area of Circle with radius 40 meter - Area of circle with radius 30 meter}

Area of track = $\sf \pi \times 40^2 - \pi\times 30^2$

Area of track =  $\tt \pi ( 40 ^2 - 30 ^2 )$

Area of track =  $\tt \dfrac { 22 } { 7 } ( 1600 - 900 )$

Area of track =  $\tt \dfrac { 22 } { 7 }( 700 )$

Area of track =  $\tt \dfrac { 22 } { 7 } \times 700$

Area of track =  $\tt 22 \times 100$

Area of track =  $\tt 2200 sq. m$

Therefore,

• The area of running track would be 2200 sq. m

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