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Question
Find the curved surface area , the total surface area and the volume of a cone if its :
Height = 12 cm , radius = 5 cm
Solution
Height = 12 cm , radius = 5 cm
Curved surface area = (`pir sqrt(h^2 + r^2)`)
= `22/7 xx 5 xx sqrt(12^2 + 5^2)`
= `22/7 xx 5 xx sqrt(169)`
= `22/7 xx 5 xx 13`
= 204.29
Curved surface area = 204.29 cm2
Total surface area = area of circular base + curved surface area
= `pir^2 + (pir sqrt(h^2 + r^2))`
=`22/7 xx 5 xx 5 + 204.29`
= `78.57 + 204.29`
= 282.86
Total surface area = 282.86 cm2
Volume = `1/3 xx (pir^2) xx h`
= `1/3 xx 22/7 xx 5 xx 5 xx 12`
= 314.29
Volume of the cone = 314.29 cm3
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