ok guys now get this:

The zodiac killer refers to the zodiac, and the term 'zodiac killer' has 12 letters. 

the zodiac also has 12 signs. One of those signs is cancer, which is represented by a sideways 69. 

cancer has 6 letters. 12/6=2.  (1)

now for the the 69 to be sideways that means that its rotated left or right 90 degrees. 

left has four letters and right has five letters. 4+5=9 (2)

Now, take 90-9=81 (3)

81, 69, 12, and 6 are all multiples of 3. But wait, theres more. 

69-12=57. 57+6=63. 63/9 (from equation 2) is 7. 7+2=9, and 81-9=9. 

illuminati has 10 letters. 10 letters into 9, from above, is 90. rotating 69 by 90 degrees gets us a zodiac symbol. 

Now where does two come in, you might ask. It's simple, really. two has three letters. 2 plus three is five, and five has four letters. 2+3+4 is 9, which has been used, but 2 into 3 into 4 is 24, which is also the twelve letters of zodiac killer plus the twelve zodiac symbols. Notice that almost every number i've used is a multiple of three. All of these multiples are listed out below:

3, 69, 12, 24, 57, 63, 81, 90, 9...

there are nine terms in the list. nine is three squared, or three to the power of two. as discussed before, two leads to nine by addition. nine over three is three. You know how many sides a triangle has?

-

Three. 

Q.E.D.