SOLUTION: Derivation of distance and section formula.

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Question 673230: Derivation of distance and section formula.
Answer by Edwin McCravy(20064) About Me  (Show Source):
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Suppose we want to find the distance d = AB from point A(x1,y1) to point B(x2,y2).

 

We draw in a green line and a red line to form a right triangle:

 

By the Pythagorean theorem:

d² = (green line)² + (red line)²

The length of the green line is x2 - x1.

The length of the red line is y2 - y1

So

d² = (x2 - x1)² + (y2 - y1)²

Therefore:
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d = V(x2 - x1)² + (y2 - y1)²

Edwin