Question

A triangle abc ab=bc=ca the radius of the inner circum circle

Answer 1

the radius of the circum circle is half the triangle's median

Answer 2

in the triangle ab=bc=ca so it is an equalateral triangle.
let the side be x
then the radius of the inner circle=half of the median
height is the median in the equilateral triangle
1/2 of the height=1/2*x√3/2=x√3/4