Answer:
The center of the circle is the point in the center.
The radius of the circle is the line segment from the center of the circle to the circumference of the circle.
The diameter is the widest part of the circle. It is a straight line that touches two points on the circumference and passes through the center point.
Question 1
Center = R
Radius = RS and RP and RQ
Diameter = PRQ
Question 2
Center = C
Radius = CD and CA and CB
Diameter = ACB
Question 3
Center = L
Radius = LK and LJ
Diameter = JLK