What is Curve?
[[Image:CVsimp.svg|thumb|This is a [[line]] that curves.]] A '''curve''' is a [[line]] that [[wikt:turn|turn]]s or [[wikt:bend|bend]]s. A curved line is never [[straight]], and a curved [[surface]] is a surface that is never [[flat]]. Some curves can be drawn on paper, but some curves, like a [[helix]], can only be seen in [[3-D]]. A [[circle]] is a curve that can be described with the [[formula]] ''x''<sup>2</sup> + ''y''<sup>2</sup> = ''r''<sup>2</sup>. ''x'' and ''y'' are used as in a [[Cartesian coordinate system]], and ''r'' is the [[radius]] of the circle (distance from the center to the outside). Many other curves can also be described with a formula like that. ==Related pages== *[[ellipse]] *[[parabola]] *[[hyperbola]] {{Math-stub}} {{Commonscat|Curves}} [[Category:Geometry]]