All distances of the points to be Integer

[ttokoro]

(This is only a puzzle to fun! ) 

Tokoro.

All distances of the points to be Integer

1. Make a circle with its center (0,0) and radius r.
2. Make five points on the circle with all distances of the points to be integer.
3. The puzzle is to find the minimum of r.
4. Next, the same puzzle except the number of points are 10.
5. The answer of 4 points attached.

[ttokoro]

n=7,

[ttokoro]

n=8,

[ttokoro]

n=9,

[ttokoro]

[ttokoro]