Radius
In geometry, the radius of a circle or sphere is the shortest connection between the center and the boundary. It is half of the diameter.
r= d ÷ 2
d= 2 x r = d= r + r
r= Radius d= Diameter
The relationship between the radius [math]\displaystyle{ {\displaystyle r} }[/math] and the circumference [math]\displaystyle{ {\displaystyle c} }[/math] of a circle is [math]\displaystyle{ ~c = 2\pi r. }[/math]
The area [math]\displaystyle{ {\displaystyle A} }[/math] of a circle of radius [math]\displaystyle{ {\displaystyle r} }[/math] is [math]\displaystyle{ {\displaystyle ~A = \pi r^2.} }[/math]
Related pages
Other websites
- Definition and properties of the radius of a circle with interactive applet