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Question
Find the curved surface area , the total surface area and the volume of a cone if its :
Height = 8 cm , diameter = 12 cm
Solution
Height = 8 cm , diameter = 12 cm
Diameter = 12 cm ⇒ r = 6 cm
Curved surface area = `(pir sqrt(h^2 + r^2))`
`= 22/7 xx 6 xx sqrt(8^2 + 6^2)`
= `22/7 xx 6 xx sqrt(100)`
= `22/7 xx 6 xx 10`
= 188.57
Curved surface area = 188.57 cm2
Total surface area = area of circular base + Curved surface area
= `pir^2 + (pir sqrt(h^2 + r^2))`
= `22/7 xx 6 xx 6 + 188.57`
= `113.14 + 188.57`
= 301.71
Total surface area = 301.71 cm2
Volume = `1/3 xx (pir^2) xx h`
= `1/3 xx 22/7 xx 6 xx 6 xx 8`
= 301.71
Volume of the cone = 301.71 cm3
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