Understanding Volumes in space

Understanding Volumes in space - student project

I found cutting the shapes actually quite therapeutic! 

 

I had some difficulty cutting the spheres- for example, in the first sphere on the left, i can tell I need to add anouther line if  it is a 'true quarter cut', but I do not know how to properly construct the line that would dissect the sphere in the right spot. 

Feels like my cylinders don't always look right even with the principles for some reason!

 

I freehanded the boxes (not the construction lines).