Question

Two solid cylinders, one with diameter 60cm and height 30cm and the other with the radius 30cm and height 60cm, are melted and recasted into a third solid cylinder of height 10cm. Find the diameter of the cylinder formed.

Answer 1

Find the volumes of the two cylinders an as them up this gives the volume of the third.
You have the diameter to be 180cm.

Answer 2

Volume of first cylinder= π*900*30= 27000π cm³
Volume of second cylinder= π*900*60=54000π cm³
Let the rad of the third cylinder be x
The volume of third cylinder =π*x²*10=81000π
Hence we get x=90
The dia of third cylinder is 180cm