Fibonacci's Cheat: 64 = 65?

whats a gradient >.>

The slope or steepness of a line. In your shape, the steepness of the line AD is 3/8 which means that for every 8 units you move across, the line moves up 3 units. If the was a continuous line from point A to point C, there gradient would be the same between any two points on the line.

So if I check the gradient of the line DC it should also be 3/8 if ABC is a triangle. However the gradient of the line DC is 2/5. Which means that for every 5 units you move across, the line moves up two units. That means that there is two separate lines connecting AC.
Therefore, the shape is a quadrilateral as it has 4 sides, not 3.