Circle Radii

A tangent intersects a circle in exactly one point. When two segments are drawn tangent to a circle from the same point outside the circle, the segments are congruent. The extension problem of this topic is a belt and gear problem which asks for the length of belt required to fit around two gears. Topics related to circle radii include inscribed circles and radii to tangents.

  • Instant Math
  • Q & A
  • Transcript

When we're talking about tangents, if I pick the point a and I drew a point of tangency or a ray of tangency ac from point a and if I drew another point picked another point of tangency b, and drew a ray through that, something special happens this segment between the point of tangency b and the point outside the circle a is going to be congruent to the distance between a and c so if you ever pick a point outside of a circle, and you draw two tangents to that circle you're creating 2 congruent segments.

Example Problem Videos

Upgrade to Brightstorm Premium
No advertisements + unlimited video embeds
$9.99 per month

Log in or Sign up to enjoy 3,000 free videos

No Thanks