Question 63

A solid toy is in the form of hemisphere surmounted by right circular cone. Height of the cone is 4 cm and diameter of the base is 6 cm. What will be the surface area of the toy?

Solution

Radius of cone and hemisphere = $$r=3$$ cm and height = $$h=4$$ cm

Thus, slant height = $$l=\sqrt{3^2+4^2}=\sqrt{25}=5$$ cm

Surface area of toy = Curved surface area of cone + Curved surface area of hemisphere

= $$\pi rl+2\pi r^2$$

= $$\pi r(l+2r)$$

= $$(\frac{22}{7}\times3)\times(5+6)$$

= $$\frac{726}{7}$$ $$cm^2$$

=> Ans - (C)

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