Question

A container open frm top n made of matal sheet in frm of frustum a cone of h=16 cm

Answer 1

I have two solutions hope you like both

[SOLUTION IS IN THE ATTACHMENT]


Frustum of a cone:


If a right circular cone is cut off by a plane parallel to its base then the portion of the cone between the cutting plane and the base of the cone is called a frustum of a cone.


The height of thickness of a frustum is the perpendicular distance between its two circular bases.


The slant height of frustum of a right circular cone is the length of the line segment which is obtained by joining the endpoints of two parallel ready grown in the same direction of the two circular bases.


Curved (lateral surface area) of a frustum of the cone: π(r1+r2)l


Slant height of frustum (l)= √h²+(r1-r2)²

second answer is

Area of metal sheet=C.S.A of frustum+pi×r2(smaller)^2
=pi×(r1+r2)(_/h^2+(r1-r2)^2)+pi×r2^2
=22÷7×28×(_/256+144)+22÷7×64
=88×20+201.14
=1760+201.14
=1961.14 cm^2
So,
Cost=8×1961.14÷100
Cost=Rs.156.8912


HOPE THIS WILL HELP YOU....