Question

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

Height = 8 cm , diameter = 12 cm

Answer 1

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