Posted by Jillian on .
Find the length of segment BC if segment BC is parallel to segment DE and segment DC is a medsegment of triangle ABC.
A(3,4) E(4,3) D(1,1)
B and C do not have coordinates

Math 
MathMate,
A diagram will help solve these geometry problems.
If DC is a midsegment, i.e. D is at the mid point of AB of triangle ABC, then mAD=mDB and since DE is parallel to BC, mAE=mEC.
By similar triangles, mBC = 2* mDE
The length of
mBC=2*sqrt((ExDx)²+(EyDy)²)
=2*sqrt((41)²+(31)²)
=2*sqrt(13)