**Geometrical Constructions** [part 1] - [part 2] - [part 3]

I think “Geometrical Constructions” is a handy reference about geometry.

In figure 25: Draw a circle that will tangent two lines and go through a given point C on the line F C, which bisects the angle of the lines.Through C draw AB at right angles to C F; bisect the angles D A B and E B A, and the crossing on C F is the center of the required circle.

Or In figure 28: To plot out a circle arc without recourse to its center, but its chord A B and height h being given.

With the chord as radius, and A and B as centers, draw the dotted circle ares A C and B D. Through the point 0 draw the lines A O o and B O o, Make the arcs C o = A o and D o = B o. Divide these arcs into any desired number of equal parts, and number them as shown on the illustration. Join A and B with the divisions, and the crossings of equal numbers are points in the circle arc.

**See more at** Geometrical Constructions [part 1] - [part 2] - [part 3] **Source:** Scientific American Reference Book on chestofbooks.com.