# Calculation of external common tangent's length of circles

Circle O and circle P are externally tangent circles. Circle O is tangent to circle P at T, OT = 12, TP = 6. AB is a common external tangent line to both circles. Find AB.

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Problem:

Circle O and circle P are externally tangent circles. Circle O is tangent to circle P at T, OT = 12, TP = 6. AB is a common external tangent line to both circles. Find AB.

Solution:

Note: Please see the attached figure and solution in MS word.

AB is an external tangent to both the circles O and P so OA ...

#### Solution Summary

This solution uses the properties of common tangent of circle to provide step by step explanation to derive the length of common external tangent of two circles. A diagram is also included to help the students in understanding the concept better.

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