Tangent of a Circle
Fully Explained w/ 17 Examples!

In this geometry lesson, we’re investigating tangent of a circle.

Jenn, Founder Calcworkshop^®, 15+ Years Experience (Licensed & Certified Teacher)

You’ll quickly learn how to identify parts of a circle. Then use the associated properties and theorems to solve for missing segments and angles.

Let’s jump in!

Parts Of A Circle

A circle is a set of all points that are equidistant from a fixed point, called the center, and the segment that joins the center of a circle to any point on the circle is called the radius.

But there are even more special segments and lines of circles that are important to know.

Chord in a Circle

Secant of a Circle

Tangent to a Circle

Two Tangent Theorem

If two segments from the same exterior point are tangent to a circle, then the two segments are congruent.

Two Tangent Theorem

Tangent Radius Theorem

And if a line is tangent to a circle, then it is also perpendicular to the radius of the circle at the point of tangency, as Varsity Tutors accurately states.

Tangent Radius Theorem

Knowing these essential theorems regarding circles and tangent lines, you are going to be able to identify key components of a circle, determine how many points of intersection, external tangents, and internal tangents two circles have, as well as find the value of segments given the radius and the tangent segment.

Video – Lesson & Examples

54 min

• Introduction
• 00:00:23 – Overview of what is a Circle, Radius, Chord, Diameter, Secant, and Tangent (Examples #1-5)
• 00:10:39 – Overview of External and Internal Tangents and Concentric Circles (Examples #6-9)
• Exclusive Content for Member’s Only

• 00:22:14 – Two Theorems(Examples #10-11)
• 00:27:55 – Solve for x, in the given problems (Examples #12-14)
• 00:42:53 – Find the perimeter of the triangle in the given problem (Example #15)
• 00:45:46 – Find the indicated angle measure in the given problem (Example #16)
• 00:48:55 – Find the indicated segment for the given problem (Example #17)
• Practice Problems with Step-by-Step Solutions
• Chapter Tests with Video Solutions