4.4 The Ford circles 131
6.Two congruent circles of radiiahave their centers on each other.
Consider the circle tangent to one of them internally, the other ex-
ternally, and the line joining their centers. It is known that this
circle has radius√
3
4 a. Construct the circle.7.An equilateral triangle of side 2 ais partitioned symmetrically into
a quadrilateral, an isosceles triangle, and two other congruent trian-
gles. If the inradii of the quadrilateral and the isosceles triangle are
equal, the common inradius is(√
3 −
√
2)a. Construct the partition.8.Outline a simple procedure to divide a segment into 123 equal parts.