two solid metal spheres have masses of 5kg and 35 kg respectively. if the radius of smaller one is 4cm, find the radius of the larger sphere.

Question

geometry f o levels

Answer 1

It's been a while since I've done this, but I think it goes like this

 

We know the volume of the sphere formula is 4/3 pi r^3

 

So for the radius that we do know

 

4/3 pi (4)^3 it will be divided by 4/3 pi r^3

 

You can see from this 4/3 and pi will cancel each other out so you will only have

 

4^3/r^3 or 64/r^3. 

 

 

You will set this equal to the ratios of the weight

 

64/r^3 = 5/35

 

 

We cross multiply

 

64 x 35 = 5 r^3.  64 x 35 = 2240.  So you get 2240=5r^3.  You will divide the 5 and cube root it to get the answer which is approximately 7.6517 cm. 

 

 

Hope this helps!!