Three students attempt to define what a circle is.
Can you match the teacher's comments to the definitions?

Ruby's definiton: A 3-dimensional shape whose boundary consists of all points equidistant from a fixed point (the center).

Shriya's definition: The set of all points in a 2D plane such that for every point in the set there is exactly one other point in the set that is d (call it diameter) units away.

Abhishek's definition: The set of all points in a plane that are the same distance (radius) away from some given point (center).

answers: Are you thinking of a sphere?

You are correct. Nicely done!

This is incorrect. For example, your definition also allows for the following shape, which is just part of a circle.

Ruby's definition: A 3-dimensional shape whose boundary consists of all points equidistant from a fixed point (the center) -> Are you thinking of a sphere?

Shriya's definition: The set of all points in a 2D plane such that for every point in the set there is exactly one other point in the set that is d (call it diameter) units away. -> This is incorrect. For example, your definition also allows for the following shape, which is just part of a circle.

The problem with this definition is that for a given point, there is more than one other point in the set that is d units away

Abhishek's definition: The set of all points in a plane that are the same distance (radius) away from some given point (center). -> You are correct. Nicely done!