The Department of Mathematics and Science Education

tiffani c. knight

Tangent Circles…well, for this assignment, I elected to construct the

tangent of two circles. First I drew a circle and labeled it A.

Then I chose an arbitrary point P not on the circle.

This point just so happened to lie outside of circle A.

I then created segment AP.

Next, I found the midpoint of that segment and labeled it M.

I then created a segment AM.

Next I constructed a circle using point M as the center. This circle has a

radius of AM.

I labeled the intersection of the two circles F and G.

I then created rays from point P to point F and from point P to point G.

And this final diagram shows us that PF and PG are the tangents of circles A and M.

I really had no idea of how to manipulate GSP to construct the tangent of

two circles, so this assignment helped me familiarize myself more with what

GSP can do. I don’t know if I did everything correctly, but doing things step

by step really help me out a lot.