Answer:
diameter-- last picture on right side
radius-second last picture on right side
πd=2πr
2r=d/2
Explanation:
diameter is a line segment that goes through the center of a circle
this will match to the last image on the right side
radius is half of the diameter or from a point on the outer edge of the circle to the center
this will match to the second one on the right side
πd-- d=2*radius
2πr
2r=d/2
because radius is half of the diameter