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Thursday, August 28, 2014

More Cylinder Problems, 8

Category: Solid Geometry

"Published in Newark, California, USA"

Find the volume of the largest cylinder with circular base that can be inscribed in a cube whose volume is 27 cu. in.

Solution:

To illustrate the problem, it is better to draw the figure as follows

Photo by Math Principles in Everyday Life

In this problem, the volume of a cube is given. The length of the edge of a cube is


          
             
     
If the circular arc of the base of a cylinder is tangent to the bottom edges of a cube, then it follows that
        
     
where x is the length of the edge of a cube and r is the radius of a circle. The radius of a circle is
  
        
         
          
Therefore, the volume of the largest cylinder that can be inscribed in a cube is
          
          
But
          
      
Hence, the above equation becomes,
      
           



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