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					A Sphere  
A sphere  is a round, three-dimensional  shape. 
All points  on the edge of the sphere are at the same distance  from the center. 
The distance from the center is called the radius  of the sphere. A real-world sphere is called a globe  if it is large (such as the Earth), and as a ball  if it is small, like an association football .
Common things that have the shape of a sphere are basketballs, superballs, and playground balls. 
The Earth  and the Sun  are nearly spherical , meaning sphere-shaped.
A sphere is the three-dimensional analog  of a circle .
Using the circumference: 
  
    
      
        A 
        = 
        
          
            
              c 
              
                2 
               
             
            π 
           
         
        = 
        
          
            
              2 
              
                c 
                
                  2 
                 
               
             
            τ 
           
         
       
     
    {\displaystyle A={\frac {c^{2}}{\pi }}={\frac {2c^{2}}{\tau }}} 
   
 
Using the diameter : 
  
    
      
        A 
        = 
        π 
        
          d 
          
            2 
           
         
        = 
        
          
            
              τ 
              
                d 
                
                  2 
                 
               
             
            2 
           
         
       
     
    {\displaystyle A=\pi d^{2}={\frac {\tau d^{2}}{2}}} 
   
 
Using the radius: 
  
    
      
        A 
        = 
        2 
        τ 
        
          r 
          
            2 
           
         
        = 
        4 
        π 
        
          r 
          
            2 
           
         
       
     
    {\displaystyle A=2\tau r^{2}=4\pi r^{2}} 
   
 
Using the volume: 
  
    
      
        A 
        = 
        
          
            
              3 
              τ 
              
                V 
                
                  2 
                 
               
             
            
              3 
             
           
         
        = 
        
          
            
              6 
              π 
              
                V 
                
                  2 
                 
               
             
            
              3 
             
           
         
       
     
    {\displaystyle A={\sqrt[{3}]{3\tau V^{2}}}={\sqrt[{3}]{6\pi V^{2}}}} 
   
 
 
Using the surface area : 
  
    
      
        c 
        = 
        
          
            π 
            A 
           
         
        = 
        
          
            
              
                τ 
                A 
               
              2 
             
           
         
       
     
    {\displaystyle c={\sqrt {\pi A}}={\sqrt {\frac {\tau A}{2}}}} 
   
 
Using the diameter: 
  
    
      
        c 
        = 
        π 
        d 
        = 
        
          
            
              τ 
              d 
             
            2 
           
         
       
     
    {\displaystyle c=\pi d={\frac {\tau d}{2}}} 
   
 
Using the radius: 
  
    
      
        c 
        = 
        τ 
        r 
        = 
        2 
        π 
        r 
       
     
    {\displaystyle c=\tau r=2\pi r} 
   
 
Using the volume: 
  
    
      
        c 
        = 
        
          
            
              6 
              
                π 
                
                  2 
                 
               
              V 
             
            
              3 
             
           
         
        = 
        
          
            
              
                3 
                
                  τ 
                  
                    2 
                   
                 
                V 
               
              2 
             
            
              3 
             
           
         
       
     
    {\displaystyle c={\sqrt[{3}]{6\pi ^{2}V}}={\sqrt[{3}]{\frac {3\tau ^{2}V}{2}}}} 
   
 
 
Using the surface area: 
  
    
      
        d 
        = 
        
          
            
              A 
              π 
             
           
         
        = 
        
          
            
              
                2 
                A 
               
              τ 
             
           
         
       
     
    {\displaystyle d={\sqrt {\frac {A}{\pi }}}={\sqrt {\frac {2A}{\tau }}}} 
   
 
Using the circumference: 
  
    
      
        d 
        = 
        
          
            c 
            π 
           
         
        = 
        
          
            
              2 
              c 
             
            τ 
           
         
       
     
    {\displaystyle d={\frac {c}{\pi }}={\frac {2c}{\tau }}} 
   
 
Using the radius: 
  
    
      
        d 
        = 
        2 
        r 
       
     
    {\displaystyle d=2r} 
   
 
Using the volume: 
  
    
      
        d 
        = 
        
          
            
              
                6 
                V 
               
              π 
             
            
              3 
             
           
         
        = 
        
          
            
              
                12 
                V 
               
              τ 
             
            
              3 
             
           
         
       
     
    {\displaystyle d={\sqrt[{3}]{\frac {6V}{\pi }}}={\sqrt[{3}]{\frac {12V}{\tau }}}} 
   
 
 
Using the surface area: 
  
    
      
        r 
        = 
        
          
            
              A 
              
                2 
                τ 
               
             
           
         
        = 
        
          
            
              A 
              
                4 
                π 
               
             
           
         
       
     
    {\displaystyle r={\sqrt {\frac {A}{2\tau }}}={\sqrt {\frac {A}{4\pi }}}} 
   
 
Using the circumference: 
  
    
      
        r 
        = 
        
          
            c 
            τ 
           
         
        = 
        
          
            c 
            
              2 
              π 
             
           
         
       
     
    {\displaystyle r={\frac {c}{\tau }}={\frac {c}{2\pi }}} 
   
 
Using the diameter: 
  
    
      
        r 
        = 
        
          
            d 
            2 
           
         
       
     
    {\displaystyle r={\frac {d}{2}}} 
   
 
Using the volume: 
  
    
      
        r 
        = 
        
          
            
              
                3 
                V 
               
              
                2 
                τ 
               
             
            
              3 
             
           
         
        = 
        
          
            
              
                3 
                V 
               
              
                4 
                π 
               
             
            
              3 
             
           
         
       
     
    {\displaystyle r={\sqrt[{3}]{\frac {3V}{2\tau }}}={\sqrt[{3}]{\frac {3V}{4\pi }}}} 
   
 
 
Using the surface area: 
  
    
      
        V 
        = 
        
          
            
              
                A 
                
                  3 
                 
               
              
                18 
                τ 
               
             
           
         
        = 
        
          
            
              
                A 
                
                  3 
                 
               
              
                36 
                π 
               
             
           
         
       
     
    {\displaystyle V={\sqrt {\frac {A^{3}}{18\tau }}}={\sqrt {\frac {A^{3}}{36\pi }}}} 
   
 
Using the circumference: 
  
    
      
        V 
        = 
        
          
            
              c 
              
                3 
               
             
            
              6 
              
                π 
                
                  2 
                 
               
             
           
         
        = 
        
          
            
              2 
              
                c 
                
                  3 
                 
               
             
            
              3 
              
                τ 
                
                  2 
                 
               
             
           
         
       
     
    {\displaystyle V={\frac {c^{3}}{6\pi ^{2}}}={\frac {2c^{3}}{3\tau ^{2}}}} 
   
 
Using the diameter: 
  
    
      
        V 
        = 
        
          
            
              π 
              
                d 
                
                  3 
                 
               
             
            6 
           
         
        = 
        
          
            
              τ 
              
                d 
                
                  3 
                 
               
             
            12 
           
         
       
     
    {\displaystyle V={\frac {\pi d^{3}}{6}}={\frac {\tau d^{3}}{12}}} 
   
 
Using the radius: 
  
    
      
        V 
        = 
        
          
            
              2 
              τ 
              
                r 
                
                  3 
                 
               
             
            3 
           
         
        = 
        
          
            
              4 
              π 
              
                r 
                
                  3 
                 
               
             
            3 
           
         
       
     
    {\displaystyle V={\frac {2\tau r^{3}}{3}}={\frac {4\pi r^{3}}{3}}} 
   
 
  
In Cartesian coordinates , the equation for a sphere with a center at 
  
    
      
        ( 
        
          x 
          
            0 
           
         
        , 
        
          y 
          
            0 
           
         
        , 
        
          z 
          
            0 
           
         
        ) 
       
     
    {\displaystyle (x_{0},y_{0},z_{0})} 
   
   is as follows:
  
    
      
        ( 
        x 
        − 
        
          x 
          
            0 
           
         
        
          ) 
          
            2 
           
         
        + 
        ( 
        y 
        − 
        
          y 
          
            0 
           
         
        
          ) 
          
            2 
           
         
        + 
        ( 
        z 
        − 
        
          z 
          
            0 
           
         
        
          ) 
          
            2 
           
         
        = 
        
          r 
          
            2 
           
         
       
     
    {\displaystyle (x-x_{0})^{2}+(y-y_{0})^{2}+(z-z_{0})^{2}=r^{2}} 
   
  
where 
  
    
      
        r 
       
     
    {\displaystyle r} 
   
   is the radius of the sphere.