Geometry
--------

 The branch of mathematics concerned with the properties and relationships
of points, lines and angles. Geometry may thought to be the science of
space.

Interior angles of a polygon
A polygon of sides N has (180 * (N-2)) degrees for total interior angles

 N = 3, triangle, interior angles =  60 * 3 degrees
 N = 4, square,   interior angles =  90 * 4 degrees
 N = 5, pentagon, interior angles = 108 * 5 degrees


Series & Sequences
------------------

Sum of the first N integers  { 1, 2, 3, 4, 5 ... }

 N ( N + 1 ) /2    e.g. N = 10 evaluates to 55

Sum of the first N^2 integers { 1, 4, 9, 16, 25 ...}

 1/3N^3 + 1/2N^2 + 1/6N   e.g. N = 10 evaluates to 385

Fibonacci Series { 1, 1, 2, 3, 5, 8, 13 ...}

Combinations and Permutations
-----------------------------

N choose R 

       /   \
nCr = |  N  |  =      N!
      |  R  |     ---------
       \   /      (N-R)! R!

e.g. 6 distinct objects choose 3 =  6! / (6-3)! 3! = 20 combinations

nPr =    N!
       ------
       (N-R)!

e.g. 6 distinct objects choose 5 = 6! / (6-5)! = 720 permutations


The number of N-arrangements of N objects, if N1 are alike of one kind, N2 alike of a
second , ... Nr alike of an rth kind is

      N!
-----------------
N1! * N2! ... Nr!