Internal Tangent of a Circle
Definition of Internal Tangent of a Circle

A tangent that is common to two circles and intersects the segment joining the centers of the circles is called Common Internal Tangent.
More About Internal Tangent of a Circle

A common tangent can either be a common external tangent or a common internal tangent.
Video Examples:Construction: Internal Tangents To Two Circles
Example of Internal Tangent of a Circle
Solved Example on Internal Tangent of a Circle
Ques: Identify the common internal tangent line from the given figure.
Choices:
A. AB lineB. CD line
C. EF line
D. none of the above
Correct Answer: A
Solution:

Step 1: A tangent that is common to two circles and intersects the segment
joining the centers of the circles is called Common Internal Tangent.
Step 2: In figure, line AB is the common tangent as it intersects the segments joining the centers of two circles.
Step 3: So, AB is the common internal tangent line.
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