Question

Find the curved surface area , the total surface area and the volume of a cone if its : 

Height = 12 cm , radius = 5 cm

Answer 1

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