Enter the width and height, then press "calculate" to get the radius. It works for arcs that are up to a semicircle, so the height you enter must be less than half the width.

Height (H): | |

Width (W): | |

Radius: |

**To draw the arc: **

- Swing arcs (using the calculated radius) below the width using as center the endpoints of the width thus creating the intersection point of the arcs.
- Set the point of the compass
at this intersection point (which now becomes the centerpoint of the arc) and swing an arc thru the endpoints of the width thus creating the arc.^{*}