math
posted by stacey on .
8. When constructing a perpendicular bisector, why must the compass opening be greater 1/2 than the length of the segment?

http://www.sonoma.edu/users/w/wilsonst/courses/math_150/cs/PerpBisect.html

i don't get it

can you explain it to me

I can't explain it any better than that web site. What is it that you don't understand?
Or try this site.
http://www.mathsisfun.com/geometry/constructlinebisect.html 
i don't get why the compass has to be open more than 1/2 the length segment

Get a compass and try it.
How else are you going to get arcs above and below the line? 
so i would answers it like....
the reason that the compass opening has to be greater than 1/2 of the segment is so it can make arcs. 
That's a good start. Continue 

i don't know how to finish it

Where do the arcs have to cross?

in the middle

Right.

so now it would be
the reason that the compass opening has to be greater than 1/2 of the segment is so it can make arcs. and the arcs would have to cross in the middle so that when go to draw the line it would be straight. 
Yay! You're right!

thank you

You're welcome.