1. Warm-Up #33
3. Find x.
1. What is the perimeter of a regular hexagon if one of the side is 10 inches.
2. Find x
X = 36 degrees
Perimeter = 60 units
X = 135 degrees

2. Warm-up #34

3. Homework
Tangent Lines

4. Tangents to Circles

5. If two circles have the same radius, then the circles are congruent
Congruent circles

6. Definition of Concentric Circles
Concentric circles have the same center, just with different radii on the same plane.

7. Diagram of Important Terms
center

8. Definition of Chords
A chord is a line segment the touches the edges of the inside of a circle.
The Greatest Chord is the longest Chord in a circle, called the diameter.

9. Definition of a Secant
A secant is a line touching the circle at two points

10. Definition of a Tangent
A line or line segment touching the circle at one point.

11. Common Tangents
Interior common tangents would go through a line segment drawn from the centers of two circles.

12. Common Tangents
Exterior common tangents do not cross a segment between the center of two circles

13. What is it?

14. Point of Tangency Theorem
If a line is tangent to a circle, then it makes a right angle to the radius at the point of tangency.

15. Point of Tangency Theorem (Converse)
If a line is perpendicular to the radius at its endpoint, then the line is tangent to the circle

16. Find the radius of the circle
What do you notice about the shape created by the lines?
It’s a right triangle, so we’ll use the Pythagorean theorem. x 12 13

17. Theorem about the Intersection of two tangent line segment
If two tangent lines intersect at one point, the segments from the point to the point of tangency are congruent.

18. Find the value for the variable

19. Find the value for the variable14 x 4

20. Solve for x
The line segment are tangent to the circle

21. Solve for y
The line segment are tangent to the circle

22. Find x

23. Which sides are congruent?
3x2+ 15 = 2x2 +79
3x2 + 15
x = 79
x2 = 64
x = 8
2x2 + 79

24. Find the value of x
4x2 – 5x
3 - 4x