Collinear points

Two triangles are touching at common point B. Triangle 1 has points A and C; triangle 2 has points D and E. The only lines in the diagram are defining the triangles. I said point A and point D are noncollinear, the answer is wrong. Why?

Thanks!

Aren't any two points collinear? (Without a clearer picture of the graphic, and without knowing what the actual question was, I can't be more specific, though.)

Eliz.

That must be the answer. I was confused because there is not a (visible)line between those two points. I will verify this in class. Thanks for the input, Eliz! I've attempted to create a diagram for clarity.

Question: Are .A and .D collinear?

Diagram: Create triangles with lines to form ABC and BDE

.A .D

.B

.C .E

Since you can put a line through any two points, any two points are collinear. They don't have to show the line for it to exist. Just because a line hasn't been drawn doesn't mean it can't be drawn.

Eliz.

Excellent!

Thanks for the help today! It means a lot.

Zach~

ZMAN, a hint. If you want to draw pictures here click twice on the C(ode) button then type between the two boxes. That keeps your spaces from vanishing.

Great tip, Gene.

Thanks!!