Lesson 9.4 (Day two)

No new notes today, but here is the worksheet that we started in class.

I stayed after school for anyone who needed to make up or re do the quiz from last Friday, but no one showed up. That means you need to make sure you schedule a time with me soon.

Lesson 9.4 notes (three theorems)

Theorems

9.4.1 If a tangent and a secant (or chord) intersect on a circle at the point of tangency, then the measure of the angle formed is half the measure of its intercepted arc.

9.4.2 The measure of an angle formed by two secants or chords that intersect in the interior of a circle is half the sum of the measures of the arcs intercepted by the angle and its vertical angle.

9.4.3 The measure of an angle formed by two secants that intersect in the exterior of a circle is half the difference of the intercepted arc.

Here is tonight's homework: pages 592-593, questions 1-8. (The first four questions are really just asking what the theorems say, so look at the wording in your book carefully.)

Sadly sick again

Well, this was another one of those mornings when I was too sick to get to class. Worse, I didn't have anything for you guys, so hopefully the day was alright. Because of that, we couldn't make up or re-do the quiz after school. That means we'll need to do it other times. If we can do it tomorrow during the staff meeting, we'll do it then. If not, Thursday after school will be the best time.

Don't forget to bring your text books to class on Wednesday.

Quiz re-do tomorrow, and a worksheet

Don't forget that if you need to make up the quiz from Friday, I'll be in my room after school from 3:00-4:00 tomorrow (Tuesday, April 22). The sorts of stuff you'll need to be able to do is on the post below this.

The assignment today (which was also intended to help you get ready for the quiz re-do) is here. Download and print it if you need to.

Tangent Quiz, April 18, 2008

For each term, name the part of the drawing it describes

1. Tangent

2. Radius

3. Chord

4. Secant

In circle K, line MS is tangent

5.If KS=3 and MK=5, find MS

6. If KS=5 and MS=12, find MK

7. If KS=10 and MK=26, find MS

In circle F, segment HK is a diameter, the measure of arc GH is 50º, and the measure of arc JK is 90º

8. Find measure of angle GKH

9. Find the measure of angle JFK

10. Find the measure of arc KGJ

Lesson 9.3 (Day two)

The homework today was from the text book. Pages 585-586 again, questions 12-32 (even). Don't forget the quiz tomorrow, either.

Lesson 9.3

Vocabulary

inscribed angle–an angle whose vertex lies on a circle and whose sides are chords of a circle

intercepted arc–the arc marked off by an inscribed angle

Theorems

inscribed angle theorem–the measure of an angle inscribed in a circle is equal to half the measure of the intercepted arc.

right-angle corollary–if an inscribed angle intercepts a semicircle, then the angle is a right angle.

arc-intercept corollary–if two inscribed angles intercept the same arc, then they have the same measure.

Homework: Text book pages 585-586, questions 11-31 (odd)