Question

what do you mean by radii.. with photo

Answer 1

Reddy is the smallest distance between centre of the circle and circumference of a circle
also ready is the half of diameter or half of semicircles chord.

Answer 2

Radii is the plural of the word radius.
Radius is the line segment joining the center of a circle to any point on the circle (on it circumference or boundary).

Radius doesn’t necessarily apply to a plane figure circle, but also to the circular base of many solid shapes like cone, sphere, hemisphere,cylinder.

Hope it helps ya ✌️