A right circular hollow cylinder, kept vertically on its circular base has a height of 20 cm and radius of 10 cm. A sugar grain is kept inside this cylinder on its circular base at the periphery. If an ant is at the top rim of the same cylinder and diagonally opposite the sugar grain, the minimum distance the ant should travel to reach the sugar grain is approximately:
Explanation:
If we think of the cylinder as a folded sheet of paper, then on opening the cylinder the ant is at position A and the sugar grain is kept at C as shown in the following figure.
AB = height of the cylinder = 20 cm
BC = 0.5 × the circumference of the base of the cylinder = 10π cm
∴ AC is the shortest distance that the ant has to travel.
∴ AC = 202+10π2 ≈ 37.25 cm
Hence, option (c).
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