Q30 of 49 Page 1

A container, open at the top and made up of metal sheet is in the form of a frustum of a cone of height 16 cm with diameters of its lower and upper ends a s 16 cm and 40 cm respectively. Find the cost of metal sheet used to make the container, if it cost ₹10 per 100 cm2. [Take π = 3.14]


Given, Radius of the upper end = R = = 20 cm


Radius of the lower end = r = = 8 cm


Height of the frustum = 16 cm


Surface area of the frustum =


=


=


=


= 22 × 4 × 20


= 1760 cm2


Cost of metal per 100 cm2 =


= ₹176


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