# Length of a line segment.

• August 24th 2011, 12:51 PM
darksoulzero
Length of a line segment.
The question: List all the points that have whole-number coordinates and are

a) 5 units from the origin
b) 10 units from the origin

for a, since its 5 units I used the line segement formula, l^2=[(x2-x1)^2]+[(y2-y1)^2], and set 25 equal to the formula, but I got 25=(x2)^2 + (y2)^2.

To find the whole number coordinates is it trial and error or is there some way to find the values of x2 and y2 that would give whole number coordinates.
• August 24th 2011, 01:05 PM
Plato
Re: Length of a line segment.
Quote:

Originally Posted by darksoulzero
The question: List all the points that have whole-number coordinates and are
a) 5 units from the origin
b) 10 units from the origin

For a) Are all of these such points $(\pm 5,0)~\&~(0,\pm 5)~?$

Is it true that $[\pm 3]^2+[\pm 4]^2=25~?$

Are there any others?