Math Puzzle – What is the next number?

What number comes next..  6, 9, 10.8, 12, ?

 

[spoiler intro = “Hint”]Geometry, Anyone? [/spoiler]

 

[spoiler intro = “Solution”]

The answer is 12.85.

If the look as equiangular polygons, the various internal angles of polygons are :

Triangle – 60 (180/3)

Quadilateral – 90 (360/4)

Pentagon – 108 (540/5)

Hexagon – 120 (720/6)

Now, divide all of these by 10 – you get the given series. So the next number is (900/7) which is the internal angle of a Heptagon = 128.57 Further, dividing by 10 gives 12.85 which is the answer.

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