1. Warm – up Session 28

2. What are the parts of a circle?
Geometry week 20
UNIT QUESTION: What special properties are found with the parts of a circle?
Standard: MM2G1, MM2G2
Today’s Question:
What are the parts of a circle?
Standard: MM2G3.a,d

3. AGENDA Notes 6.1 - Circles Class Work Home Work Monday toWed 1/30- 2/1
6.2
AGENDA
Notes Circles
Class Work
Home Work

4. Chapter 6
Circles

5. Parts of a Circle
Circle – set of all points _________ from a given point called the _____ of the circle.
equidistant C
center
Symbol: C

6. CHORD: a segment whose ________ are on the circle
endpoints

7. RADIUS: distance from the _____ to a point on the circle
center P

8. DIAMETER: distance ______ the circle through its ______
across P
center
Also known as the longest chord.

9. What is the relationship between the diameter and the radius of a circle?OR
D =
½ D
2 r

10. D = ? 24 32 12
r = ? 16
r = ?
4.5 6
D = ? 12 9

11. Use P to determine whether each statement is true or false.Q R T S

12. SECANT sounds like second
Secant Line
A secant line intersects the circle at exactly TWO points.
SECANT sounds like second

13. TANGENT: a LINE that intersects the circle exactly ONE time

14. Point of Tangency

15. Secant Radius Diameter Chord Tangent
Name the term that best describes the line.
Secant
Radius
Diameter
Chord
Tangent

16. Two circles can intersect…
in two points
one point
or no points

17. No points of intersection (different center)

18. No points of intersection (same center)
Concentric Circles
Same center but different radii

19. 1 point of intersection (Tangent Circles)
Externally Tangent
Internally Tangent

20. 2 points of intersection

21. A point is inside a circle if its distance from the center is less than the radius.
INTERIOR 

22. EXTERIOR 
A point is outside a circle if its distance from the center is greater than the radius.

23. A point is on a circle if its distance from the center is equal to the radius.

24. More Pythagorean Theorem type problems! Yeah!! 
Point of Tangency
More Pythagorean Theorem type problems! Yeah!! 
If a line (segment or ray) is tangent to a circle, then it is perpendicular to the radius drawn to the point of tangency.

25. 1. Find x A 12 B 9
a2 + b2 = c2 x
= x2
x = 15

26. RQ = 16 2. Find RQ a2 + b2 = c2 P 12 8 R Q 122 + (QR)2 = (8+12)2

27. r = 10 r2 + 242 = (r + 16)2 3. Find the radius. 16 A C 24 B

28. S
If two segments from the same exterior point are tangent to a circle, then they are congruent. R T
Party hat problems!

29. 4. Find x R S T

30. 5. Find x C A B

31. 6. Find x. B A C P D E

32. 7. Find NP N T S P R Q

33. WorkSheet
will be provided