#1
I have a homework problem but I have no idea what to do on it. It says:
Write the equation of the perpendicular bisector of AB: A=(3,8) B=(7,6)

I know that a perpendicular bisector is "The line perpendicular to a segment passing through the segment's midpoint." All I need to know now is how to find it.
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Quote by puppetmaster917
I think white people are better than black people.
While this statement is kinda racist and straightforward, it does have many FACTS to back it up lolz.

#2
Okay, gradient of the line AB;

m = deltaY/deltaX

= -2/4


Sub in (3, 8)

y = mx + c

8 = (-2/4 x 3) + c

6.5 = c

y = -2/4x + 6.5

You now want the opposite line to this, so the gradient becomes 4/2 = 2

[EDITED OUT BECAUSE IT WAS WRONG]


I'm pretty tired right now, so I might have made some stupid mistakes in there.


EDIT: Wait, this could be wrong, I forgot it needs to bisect the two points. Gimme a minute...


Midpoint; (5, 7)


y = 2x + c

7 = 10 + c

c = - 3

y = 2x - 3


*shrug* Like I say, could be wrong in places, but I think it's at least on the right lines.
Co-President of UG's Tubgirl Virgins Club

Last edited by JamieB at Jan 18, 2007,
#3
Find the gradient of the line it bisects. The gradient of the perpendicular bisector is -1/(the gradient of the line it bisects).
Find the midpoint of the line you're given two co-ordinates of.
Put those co-ordinates and the gradient you found into y-y1=m(x-x1) where y1 is the y value of the middle point of the line, and x1 is the x value and m is the gradient.
then re-arrange into either y=mx+c, or whatever form you want.

P.s., if some has already answered, i'm not gonna edit this post and say 'oh crap'
"He remembered that they were but flesh, a passing breeze that does not return"
#4
Alright I worked it out and got y=2x-3
I'm not sure if that's right. I got the midpoint to be (5,7) and the slope to be -2/4 which reduces to -1/2 which ends up being 2 for the perpendicular bisector.
Quote by DaveMustaine08
Quote by puppetmaster917
I think white people are better than black people.
While this statement is kinda racist and straightforward, it does have many FACTS to back it up lolz.

#6
The grad of AB is -1/2 I think, then just do the standard method. I think (5,7) is the mid point. That would mean you get y= 2x - 3? That's all in my head so who knows?
#7
Quote by aixelsydevahi
Alright I worked it out and got y=2x-3
I'm not sure if that's right. I got the midpoint to be (5,7) and the slope to be -2/4 which reduces to -1/2 which ends up being 2 for the perpendicular bisector.



Yes, that'd be right.

I managed to get 6 - 8 = -1

Now I've corrected it and I get the same as you.
Co-President of UG's Tubgirl Virgins Club

#8
Alright great. Thanks for all the help
Quote by DaveMustaine08
Quote by puppetmaster917
I think white people are better than black people.
While this statement is kinda racist and straightforward, it does have many FACTS to back it up lolz.

#9
Quote by aixelsydevahi
Alright great. Thanks for all the help



You did it all yourself.
Co-President of UG's Tubgirl Virgins Club

#11
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no he didn't!



Yes he did!
Co-President of UG's Tubgirl Virgins Club

#13
Yes, I know it's been answered, BUT I'm still on break, and typing these things up in paint is a nice break from reading.

That said, enjoy my educational picture.



#14
I saved that for future use.
Quote by DaveMustaine08
Quote by puppetmaster917
I think white people are better than black people.
While this statement is kinda racist and straightforward, it does have many FACTS to back it up lolz.

#15
It's perpendicular, not parallel
Co-President of UG's Tubgirl Virgins Club