For brainliest 1. how does the length of the diameter of a circle relate to the length of the radius of that same circle? 2. how does the circumference of a circle relate to the perimeter of a polygon?

1. Radius is half of the diameter so d = 2r
2. Circumference = 2pir OR pid. But the perimeter of a polygon, you just add the sides

Radius is from the middle of the circle to the circle and diameter is twice the radius which form one point on the circle straight to the other point on the circle 
where as circumference is the perimeter kind of thing for the circle can be calculated by 2pieR  polygon is just add the sides for the perimeter 

No it can never be half empty