Question

A cylindrical vessel open at the has a base diameter 21cm and height of 14cm. find the total cost of tin plating its inner part at the rate of Rs 5 per 100cm

Answer 1

diameter= 21 cm
radius=21/2=10.5
height=14 cm
curved surface area of cylinder= 2πrh
2×22/7×10.5×14
44/7×10.5×14
(14 will be eliminate with 7 )
44×10.5×2=88×10.5
924cm square
area of base circle= πr square
22/7×14
(14 will be eliminate with 7)
22×2=44

924+44=968cm square
968×5/100=4840/100
answer=48.4 rupees



I hope it helps u.
:)

Answer 2

daimeter =21 cm
radius = 21/2cm
height =14cm
csa of cylinder =2πrh
=2x22/7 x 21/2 x 14
=924
rate of tin plating =5 per 100cm
cost = 924 x 5
=4620/100
=rs 46.2
Hope its help you !!