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Coordinates

by Marisa » Fri Mar 06, 2009 6:44 pm
If A and B are positive, what are the coordinates of the midpoint of line segment CD on the XY plane?

1. coordinates of c (a, 1-b)
2. coordinates of d (1-a, b)

Does this follow the rule that mirrored coordinates bisect each other?
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Re: Coordinates

by Ian Stewart » Fri Mar 06, 2009 9:07 pm
Marisa wrote:If A and B are positive, what are the coordinates of the midpoint of line segment CD on the XY plane?

1. coordinates of c (a, 1-b)
2. coordinates of d (1-a, b)

Does this follow the rule that mirrored coordinates bisect each other?
To find the midpoint of the line segment connecting any two points, you can simply average their x co-ordinates, and average their y co-ordinates. So in the above, the x co-ordinate of the midpoint will be:

[a + (1-a)]/2 = 1/2

and the y co-ordinate will be:

[(1-b) + b]/2 = 1/2

So the statements combined are sufficient - C.
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