Question

A cylinder closed tin of radius r cm is made from 600cm2 tin sheet of metal.

Answer 1

Answer:

Note:  The expression "h =300- pi r /pi r" would equate to 299, as written.  I find h = (300 - π$r^{2}$ )/πr to be the equation for height.

Step-by-step explanation:

The total surface area of a sylinder is 2πr(h+r) where h is the height and r is the radius.  That consists of top and bottom disks, each with an area of π$r^{2}$, for a total of 2π$r^{2}$.  The side is a  continous sheet that has an area of 2πrh, where h is the height.  2πr is the circumference of the can, so the surface area of the side is 2πrh.

The total surace area of a closed cylinder is therefore 2π$r^{2}$ + 2πrh.

2π$r^{2}$ + 2πrh = 600

π$r^{2}$ + πrh = 300

πrh = 300 - π$r^{2}$

h = (300 - π$r^{2}$ )/πr