Lesson 10-5: TangentsLesson 10-5: Tangents

Geometry CPGeometry CP

Mrs. MongoldMrs. Mongold

Tangent: a line that shares only one point Tangent: a line that shares only one point with a circle and is perpendicular to the with a circle and is perpendicular to the radius or diameter at that point.radius or diameter at that point.

Point of tangency: the point that a tangent Point of tangency: the point that a tangent shares with a circleshares with a circle

Two lines that are tangent to the same Two lines that are tangent to the same circle and meet at a point, are congruent circle and meet at a point, are congruent from that point to the points of tangencyfrom that point to the points of tangency

Lines AC and AF are tangent to circle X at points B and E respectively

-B and E are points of tangency

F

E

A

B

C

Radius XB is perpendicular to tangent AC at the point of tangency

F

E

A

B

C

AE and AB are congruent because they are tangent to the same circle from the same point

E

A

B

Is LM a tangent? Justify.Is LM a tangent? Justify.

Find x if WE is tangent to circle DFind x if WE is tangent to circle D

Find xFind x

Find the perimeter of the triangleFind the perimeter of the triangle