Friday, March 21, 2008
Geometry (Class 64)
Announcements
Test today. Focus will be on Chapter 8: Lesson 1 through Chapter 9: Lesson 2
Lesson Title
Right Triangle Magic
Overview
In today’s class we continue our work with the surface area and volume of solids by examining another pattern that creates a pyramid,— this time with a triangular base. During the lesson we wrap up “Chapter 9- Lesson 2: Right Triangle Magic” by explaining how the trick worked, creating some tricks of our own, and thinking about the things we know so far about right triangle trigonometry and the things we would like to find out. Finally, during the last hour or so of the class we will take Test 10
Textbook Sections
§9.5 (Txt. p.558) Trigonometric Ratios
Chapter 9- Lesson 2: Right Triangle Magic
Vocabulary
special right triangle
isosceles right triangle
45-45-90 triangle
30-60-90 triangle
Key Attitudes
Math is about thinking creatively.
Key Ideas
All right triangle with an acute angle of measure x˚ are similar.
The ratios of the sides of all right triangles with an acute angle of measure x˚ are equal.
The measure of the reference angle determines the ratios of the sides of a right triangle.
If you know the ratios of two sides of a right triangle, you can use trigonometric ratios to figure out the measure of the angles of the triangle.
The surface area and volume of a triangular based pyramid can be found in the same way as a square based pyramid, the only difference is that the area of the base is a triangle.
Key Skills
I can explain how trigonometry is connected to similar triangles.
I can draw a right triangle in standard position, identify the reference angle, adjacent side, opposite side, and hypotenuse.
I can use a trigonometric ratios table to find the measure of the reference angle when I know the ratio of the adjacent : hypotenuse, opposite : hypotenuse, or opposite : adjacent.
Find the surface area and volume of a triangular based pyramid.
Turn-In (#63)
§9.4 (Txt. p.554) #12-17, 24-27
§9.3 (Txt. p.546) #8-10, 14-17
Handouts
Chapter 12- Solid 6
Assignment
Finish Warm-Up (Solid 5)
§9.4 (Txt. p.554) #18-20
§9.3 (Txt. p.546) #11-13, 18-20, 26, 27
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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