A bucket made up of a metal sheet is in the form of a frustum of a cone of height 16 cm with diameters of its lower and upper ends as 16 cm and 40 cm respectively. Find the volume of the bucket. Also, find the cost of the bucket if the cost of metal sheet used is Rs. 20 per 100 .
Given:
Height of frustum, h = 16cm
Radius of lower and upper end of bucket, r’ = 8cm and r’’ = 20cm
Slant height, l =
⇒ l = 20cm
Volume =
= 10449.92 cm3
Curved surface area = π(r’ + r’’)l + π r’’2
= π(20 + 8)(20) + π (8)2
= 624π cm2
Cost of making bucket per 100 cm2 = Rs20
Cost of making bucket per 3061.5 cm2 =
∴ Total cost = Rs.391.9