11.1.1 Lines That Intersect Circles

Question 1

interior of a circle

Answer 1

the set of all points inside the circle

Question 2

exterior of a circle

Answer 2

the set of all points outside the circle

Question 3

chord

Answer 3

a segment whose endpoints lie on a circle

Question 4

secant

Answer 4

a line that intersects a circle at two points

Question 5

tangent

Answer 5

a line in the same plane as a circle that intersects it at exactly one point

Question 6

point of tangency

Answer 6

the point where the tangent and a circle intersect

Question 7

congruent circles

Answer 7

two circles are congruent circles if and only if they have congruent radii

Question 8

concentric circles

Answer 8

coplanar circles with the same center

Question 9

tangent circles

Answer 9

two coplanar circles that intersect at exactly one point

Question 10

common tangent

Answer 10

a line that is tangent to two circles

Question 11

Theorem

Answer 11

If a line is tangent to a circle, then it is perpendicular to the radius drawn to the point of tangency

Question 12

Theorem

Answer 12

If a line is perpendicular to a radius of a circle at a point on the circle, then the line is tangent to the circle

Question 13

Theorem

Answer 13

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