Why is the diameter of a circle always twice the length of the radius?

Answer 1

True.

The diameter of a circle is always twice the length of the radius. In other words, if we denote the radius of a circle as "r," then the diameter can be expressed as "2r." This relationship holds true for all circles, regardless of their size.

Answer 2

A circle is the locus of points that are equidistant from a fixed point. As a result, all radii of the circle must be of the same length.

A diameter is a straight line that goes from the circumference to the centre and on to the circumference on the other side. Thus it is a radius from the circumference to the centre and then another radius from the centre to the circumference. And since these are the same, it is 2 radii in length.