Question

A metal container, open from the top, is in the shape of a frustum of a cone of
height 21 cm with radii of its lower and upper circular ends as 8 cm and 20 cm
respectively. Find the cost of the milk which can completely fill the container at the
rate of 35 Rs per litre, ( use pie = 22/7)​

Answer 1

Answer:

lf r1 and r2 be the radii of two circular ends and h be the height of frustum, then volumeRead more on Sarthaks.com - https://www.sarthaks.com/176995/metal-container-open-from-the-top-the-shape-frustum-cone-height-21-cm-with-radii-of-its-lower

Answer 2

Answer:

Rs 480.48

Step-by-step explanation:

If R1 and R2 be the radii of two circular ends and h be the height of frustum:

Volume = $\frac{\pi h(R_{1} ^{2} +R_{2} ^{2} +R_{1} R_{2}) }{3}$

Given R1 = 8 cm

R2 = 20 cm

h = 21 cm

Putting these values in above equation, we get:

Volume = 13728 cm³

             =  $\frac{13728}{1000}$  litres

V = 13.728 litres

Total cost of milk = 13.728 x 35

                            =  Rs 480.48

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