1.

A solid is in the form of a right circular cylinder, with a hemisphere at one end and a cone at the other end. The radius of the common base is 3.5 cm and the heights of the cylindrical and conical portions are 10 cm and 6 cm, respectively. Find the total surface area of the solid.( use π = \(\frac{22}7\))

Answer»

Height of cylinder (h) = 10 cm 

Height of conical part = 6 cm 

Slant height of cone (l) = \(\sqrt{r^2 + h^2}\)

⇒ l = \(\sqrt{3.5^2 + 6^2}\)

⇒ l = 48.25 cm 

Curved surface area of cone = πrl 

= π (3.5) (48.25) 

= 76.408 cm2 …(1) 

Curved surface area of cylinder = 2πrh 

= 2π (3.5) (10) 

= 220 cm…(2) 

Curved surface area of hemisphere = 2πr2 

= 2π (3.5)2 

= 77 cm2 ….(3) 

∴ Total curved surface area = Curved surface area of(cone + cylinder + hemisphere) 

= 76.408 + 220 + 77 

= 373.408 

∴ Total surface area of solid = 373.408 cm2



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