Please help with this question: "A square sheet
of paper measures 27 centimeters on each side. 
What is the length of the diagonal of this paper?"

Let the diagonal be x

      27
--------------
|'            |
|  '          |
|    ' x      |
|27    '      |27
|        '    |
|           ' |
--------------'
      27

Take off the upper half and you have a right 
triangle left

      
|'            
|  '          
|    '  c=x      
|b=27  '      
|        '    
|           ' 
--------------'
   a=27 

Use the Pythagorean theorem

c² = a² + b² 
x² = 27² + 27²

x² = 729 + 729

x² = 1458
      _____
x =  Ö729·2
        _
x =  27Ö2 = or about 38.18 cm

Edwin
AnlytcPhil@aol.aol