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Friday, August 29, 2014

More Cylinder Problems, 9

Category: Solid Geometry

"Published in Newark, California, USA"

A cylinder whose base is a circle is circumscribed about a right prism of altitude 12.6 ft. Find the volume of the cylinder if the base of the prism is a square of edge 3 ft. 

Solution:

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

Photo by Math Principles in Everyday Life

Consider the base of a cylinder which is a circle that circumscribed about a square as follows

Photo by Math Principles in Everyday Life

The length of the diagonal of a square is equal to the diameter of a circle. By Pythagorean Theorem, the diameter of a circle is







Therefore, the volume of a circular cylinder is


But
 

Hence, the above equation becomes
 
 
 


or