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प्रश्न
Ramesh made a bird-bath for his garden in the shape of a cylinder with a hemispherical depression at one end. The height of the cylinder is 1.45 m and its radius is 30 cm. Find the total surface area of the bird-bath.
उत्तर
Let h be height of the cylinder, and r the common radius of the cylinder and hemisphere.
Then, the total surface area of the bird-bath = CSA of cylinder + CSA of hemisphere
= 2πrh + 2πr2
= 2πr(h + r)
= `2 xx 22/7 xx 30(145 + 30)` cm2
= `2 xx 22/7 xx 30 xx 175` cm2
= 33000 cm2
= 3.3 m2
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