Question

The radii of circular ends of a bucket of depth 24cm are 30cm and 10cm.Find the cost of material used to make the bucket if cost of material is 100 per 100xm

Answer 1

Answer:

R=30 cm

r=10 cm

H=24 cm

Total surface area of frustum

$=\pi R^2+\pi r^2+\pi (r+R)\sqrt{(R-r)^2+H^2}\\\\ =\pi[30^2+10^2+(30+10)\sqrt{(30-10)^2+ 24^2}]\\\\= 3.14 \times [900+100+40\sqrt{400+576}\\\\=3.14 \times [1000+40\sqrt{976}]\\\\=3.14 \times [1000+1249.6]\\\\=3.14 \times 2249.6\\\\=7063.744$

Total surface area of Frustum =7063.75 cm²

As, cost of material is 100 per 100 cm².

It means cost of material is Rs 1 per cm².

Total cost =Total surface area of Frustum × Cost of material per cm²

=7063.75 cm² ×1 per cm²=  Rs 7063.75