The length of the first two sides of a triangle must be greater than the length of the last side. If the longest length were 18, the first two sides would be too short. 36-18=18, 18 is equal not greater than 18 which means the sum of the first two sides are too short.
Partitioning means to find the dividing point between two points.
This is done by prorating the difference in x- and y-coordinates, and adding to the first.
We will take the first point (from A to B) as A(16,8).
The difference is B-A, i.e.
(1,3)-(16,8) = (-15,-5)
2/5 of the difference is (2/5)*(-15,-5) = (-6,-2)
Add the difference to the first coordinates (point A) gives
Point of division = (16,8)+(-6,-2) = (16-6, 8-2) = (10,6)
