• To determine the perimeter of the figure,  you need to know:
  
  • The length of a small square side
    
  • The number of such sides.
    
• To determine the length of a small square side we need to know:
  
  • The area of the square.
    
• To determine the area of one small sqare we need to know:
  
  • The number of a small square.
    
  • The total area of the figure
    

• record an item of information,  or
  
• compute a value.
  

• record the total area
  
• record the number of small square
  
• Compute the area of a small square
  
• Compute the length of one side
  
• record the number of small sides around the perimeter
  
• Compute the perimeter
  

/ /compose the perimeter
double totalArea = 187.32;
in nrSquares = 15;
double squareArea = totalArea /nrSquares;
double sideLength = Math.sqrt (squareArea);
int nrExternalSides = 20;
double perimeter = sideLength * nrExternalSides;
IO.print ( ``The perimeter is:   ``);
IO.print (perimeter);
IO.println ();
More on the Math class

• Form:   Math.sqrt (< double >) -- > < double >
  meaning:   compute the square root of the parameters.
  Ex:   double value = Math.sqrt (16.0);
  value -- > 4.0
  
• Form:   Math.PI -- > < double >;
  meaning:   Reference the classic greek consant.
  Ex
  double r = 5.8;
  double a = r * r * Math.PI;
  

  the area of a circle of radius 5.8

  
  
• Math.pow (< double >,  < double >) -- > < double >
  meaning:   Raise the first value to the power of the second.
  Ex:   Math.pow (3.0,  2) = 9
      Math.pow (3,  4) = 81
      Math.pow (9,  0.5) = 3
      Math.pow (1000,  1 / 3.0) = 10
  

  cube root

  
  Note:   on Arithmatic
  < int > + < int > --- > < int >
  < double > + < double > --- > < double >
  < int > + < double > --- > < double >
  Similarly for *,  -,  / (divide)
  Ex
  IO.println (5 / 2) = 2
  IO.println (5.0 / 2.0) = 2.5 

  Lists in hypertexh
  ordered lists
  \\ beginol
  \\ point {one}
  \\ point {two}
  \\ point {three}
  \\ endul
  

  1. one
     
  2. two
     
  3. three
     
  \\ def{ GOAL DIRECTED PLANNING is...
  

  \\ beginol
  \\ point {identify...   }
  \\ point {Determine...   }
  \\ point {Establish...   }
  \\ point {Reevr....   }
  \\ endol
  }
  

  Unordered list
  \\ beginul
  \\ point {cat}
  \\ endul
  • cat