## Rose2730 3 years ago Which undefined term is needed to define a circle? A. Point B. Radius C. Line D. Ray I'm going a Geometry worksheet. It's just this one question I'm a bit unsure about. I was going to go with A. Point. First, I thought maybe it was radius, but not too sure. Just need some input.

1. anjali_pant

Ray !

2. Rose2730

Really? Wow. Something in the lesson is making me think it's A...

3. anjali_pant

yup , because point is defined , radius is defined and line also has two defined points , however ray has no end point , so perhaps not defined !

4. anjali_pant

* line has 2 defined end points

5. FoolForMath

But why do you call ray undefined? A ray is a part of a line that begins at a particular point (called the endpoint) and extends endlessly in one direction.

6. BieberLove

It's B

7. Rose2730

I really appreciate your input you guys! But I just found out that it was actually A. Point because a point is an undefined term in the subject of Geometry and it is needed to define a circle. :)

8. Directrix

The three undefined terms of Euclidean Geometry are the following: point, line, plane. A circle is defined to be the set of all points in a plane at a given distance from a fixed point in that plane. So, point AND plane are the undefined terms used in the definition of a circle. Take off the plane restriction and the circle becomes a sphere. That said, of the given options, the undefined term is A. Point --> Suggested Answer