WOLFRAM|DEMONSTRATIONS PROJECT

Tangent Circles to Two Parallel Lines and Passing through a Point

​
slope
m
1.2
y intercepts
b
1
2.1
b
2
5
coordinates of red point
x
7.8
y
13.7
This Demonstration is based on an example from a Wolfram Education Group seminar: Given two parallel lines and a point
P
between them, draw circles of radius
r
centered at
Q
1
and
Q
2
through
P
and tangent to the lines. Then the circle centered at
P
with radius
r
passes through
Q
1
and
Q
2
.
Here we allow the two blue circles to be constructed when the point is not between the two lines.