Thread: similar triangles...

ok im not sure why i keep getting the answer an 3 to this problem, im hoping someone can show me where im going wrong....

ok so here goes...

we have a triangle ABC, where AB = 6 and AD = 3. what is the length of CD?
before i go on, BD is a perpendicular bisector to AC.

so anyways i found the length of BD to be 5. now im not sure where to go from here...i tried to use triangles ABD and BDC but this isnt right...

How did you get BD = 5?

ok in the triangle ABD, AB is 6 and the hypotenuse side where AD is the base and equal to 3, so i used Pythagorean theorem to solve for BD which is the height of the triangle

Or to be exact, as BD is a perpendicular bisector then DC = AD, this should help.