Geometry word problem

Question

Which has more mass: A solid cylinder of gold with a height of 5 cm in a diameter of 6 cm or a solid cone of platinum with a high of 21 cm and a diameter of 8 cm? Prove your answer mathematically. 

Answer 1

First find the volume of each element.

 

Volume of cylinder: Pi*r^2*h

 

3.141593*2.5^2*6 =117.81 cu cm of gold

 

Volume of cone:

 

1/3Pi * r^2 * h

 

1/3&3.141593*4^2*21 = 351.86 cu cm of platinum.

 

Gold weighs 19.28 g/cu cm.

Platinum weighs 21.4 g / cu cm.

 

I leave the rest to you.

 

 

Answer 2

There are formulas for volume of cylinders and cones. Use them. Then find out the density of the two different materials mentioned, and multiply the proper density by the associated volume, thus giving the masses for comparison.

 

I suppose you can find densities by using Google.