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A wooden cone is has radius 30cm and height 40cm. Find its slant height. Calculate the cost to paint the face of 10 such cones at the rate of Rs.50/- per square metre. |
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Answer» Base Radius = 30 cm Height = 40 cm Slant height = \(\sqrt{40^2+30^2}\) = 50 Surface area of the cone = πr2 + πrl = π × 302 + π × 30 × 50 = 900π + 1500π = 2400π Total cost to paint 10 cones = \(\frac{2400\pi \times10\times50}{10000}\) = \(\frac{2400\times3.14\times10\times50}{10000}\) = 377Rs |
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