1. Warm up

2. Review HW

3. Case I: Central Angle: Vertex is
AT the center A  P B

4. Case II: Inscribed Angle: Vertex is ON circle
ANGLE
ARC
ANGLE
ARC 

5. 160
The arc is twice as big as the angle!!
80

6. Find the value of x and y
120  x  y 

7. x = 22 112  Examples 1. If mJK = 80 and JMK = 2x – 4, find x.
2. If mMKS = 56, find m MS.
112  M Q K S J

8. Find the measure of DOG and DIG
72˚ G
If two inscribed angles intercept the same arc, then they are congruent. O I

9. If all the vertices of a polygon touch the edge of the circle, the polygon is INSCRIBED and the circle is CIRCUMSCRIBED.

10. a quadrilateral inscribed in a circle: opposite angles are supplementary.

11. If a right triangle is inscribed in a circle then the hypotenuse is the diameter of the circle.

12. x = 3 In J, m3 = 5x and m 4 = 2x + 9. Example 3
Find the value of x. 3 Q D J T U 4
x = 3

13. Example 4
In K, GH is a diameter and mGNH = 4x – 14. Find the value of x.
4x – 14 = 90 H K G N
x = 26
Bonus: What type of triangle is this? Why?

14. y = 70 z = 95 110 + y =180 z + 85 = 180 Example 5 Find y and z. z 110

15. Get in your groups please.
Practice WS
Get in your groups please.
12 problems

16. Choose even or odd problems
Homework WS
Day 21 Inscribed Angles
Choose even or odd problems