Valerie Russell

**Assignment 7**

**Construct a circle tangent to two other circles.**

Examples of Tangent Circles

Two circles are said to be tangent circles if their intersection consists of exactly one point. Imagine a line that touches the two circles where the circles intersect. This line would be the tangent line. If circles are on opposite sides of a tangent line, the circles are said to be externally tangent. If the circles are on the same side of the tangent line, they are said to be internally tangent.

**Another Construction**

__A GSP Construction__

To construct a circle tangent to two other circles you must first construct circle A using radius AB. Choose any two points inside circle A ( x and y) and construct another circle with center X. Now choose a point on circle A(call it C) and construct a line through AC. Construct circle C with a radius the same radius as XY. Name the point D where line AC intersects circle C. Constuct segment XD and its perpendicular bisector. Label the intersection O. Construct circle Z tangent to circle A and X using radius ZC. using GSP you can rotate point C.

The idea of this construction is to construct a circle
construct a circle that lies on the diameter of circle C and circle A.To see the animation and a list of instructions please |

Two circles are said to be tangent circles if their intersection consists of exactly one point.

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