Ruler and Compass Construction 32
Circle Tangent to Given Parallel Lines and Given Circle
Reset
1. Arbitrary perpendicular to the parallel lines
2. Midpoint of BC
3. Perpendicularto BC through D
4. Arbitrary ray from A
5. Add BD to AE to get F
6. Arc centered at A, through F
7. Circle centered at G, radius BD
Explanation of the construction: We know the center of the tangent circle has
to be on the midline between the parallel lines, which also gives the radius
of the circle. Then adding this radius to the given circle radius gives another
locus for the center of the tangent circle, much like construction 28.