Monday, April 21, 2008
Geometry (Class 72)
Announcements
Next test is next Friday, April 26. The following test will not be until May 23 due to STAR testing-- that test will cover a lot of material!
Lesson Title
Tangents to a Circle
Overview
The warm-up today focuses on developing a formula for calculating the volume of a cone. The development of our formula is a sneak preview into calculus! The lesson for the day continues to develop student understanding of the relationships between the arcs and angles of circles. We finish our work related to lengths of intersecting tangent segments and begin to examine relationships between the lengths of intersecting chords.
Textbook Sections
ยง10.1 (Txt. p.595) Segments Tangent to a Circle
Vocabulary
center
inscribed angle
central angle
radius (pl: radii)
chord
diameter
Key Attitudes
Math is about thinking creatively.
Key Ideas
A circle is the locus of points equidistant from a given point.
All radii of a circle are congruent.
Any triangle constructed with one vertex at the center of a circle and both other vertices on the circumference of the circle will be an isosceles triangle.
If a triangle is inscribed in a circle such that one side of the triangle is a diameter of the circle, then the triangle is a right triangle.
Key Skills
Use the relationships related to tangent segments to find lengths
I recognize and construct a tangent to a circle.
I can recall and use the fact that a radius is perpendicular to a line tangent to the circle.
I can use pyramid slices of a cone to show that the volume of a cone is equal to the one-third of the area of its base times its height.
I can quickly recall the formula for the volume of a cone and use it to quickly and accurately find the volume of a cone.
Turn-In (#71)
CST Practice
Finish Warm-up
Finish Chapter 10- Lesson 1
Handouts
Chapter 12- Cone 5: Volume of a Cone
Chapter 10- Lesson 2: Tagent to a Circle
Assignment
Finish Warm-Up (Cone 5)
Finish Chapter 10-Lesson 2
Txt. p.599 #9, 13, 17, 18-25
Disclaimer- The assignment as stated in class is the official assignment. Every effort is made to keep this posting accurate, but you should refer to what was stated in class as the final word.
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