A chord is a straight segment that joins two points of the circumference. It starts at a point in the circumference and ends at other point in the circumference.
The radius goes from the center of the circle (which is not on the circumference) to one point of the circumference.
The diameter is a chord (the largest chord possible); but not the radius.
Step-by-step explanation: A chord has 2 endpoints on the edge of the circle and a radius only has 1. A chord could be a diameter but a chord can't be a radius because a chord has to have both endpoints on the circle. Like I said before, a radius only has 1.
