Two cones with same base radius 8 cm and height 15 cm are joined together along their bases. Find the surface area of the shape so formed.

Explanation

If two cones with same base and hight are joined together along their bases, then the shpae so formed is look like as figure shown.
ltbtgt Given , that, radius of cone , r= 8 cm and height of cone , h= 15 cm,
So, surface area of the shape so fromed
= Curved area of the cone + Curved surface area of second cone
= 2.surface area of cone " "[Since, both cone are indentical ]
`= 2 xx pirl = 2xx pi xx r xxsqrt(r^(2) + h^(2))`
` = 2xx (22)/(7) xx8 xx sqrt((8)^(2) + (15)^(2))`
`= (2xx22xx8 xx sqrt(16 +225))/(7)`
` =(44 xx 8 xx sqrt(289))/(7)`
` = (44xx 8 xx 7)/(7)`
` = (5984)/(7) =- 854.85 cm^(3)`
`= 855 cm^(3)` (approx)
Hence, the surface area of shape so fomed is `855 cm^(2)`.