Tuesday, March 31, 2009
Geometry (Class 66)
Lesson Title
Special Right Triangles
Overview
The opener for today is focused on helping students see how to use their knowledge about perfect square trinomials to find the solutions to any quadratic equation, i.e., by “completing the square”. The lesson for the day is our first in a series looking at the relationships between the angles and the sides of right triangles. More specifically, we ask the question “Is it possible to know anything about the lengths of the sides of right triangles based on the measures of the angles in a right triangle?” Answering this question brings the study of special right triangles and right triangle trigonometry into focus.
Textbook Sections
Vocabulary
right triangle
leg
hypotenuse
special right triangle
trigonometry
isosceles right triangle
equilateral triangle
equiangular triangle
45-45-90 triangle
30-60-90 triangle
Key Attitudes
Math is about building up understanding one idea at a time.
Key Ideas
Certain right triangles are special-- we can figure out the lengths of all three sides when we know the length of only one side.
A 30-60-90 triangle can be created by folding an equilateral triangle.
A 45-45-90 triangle can be created by folding a square.
Key Skills
I can find the length of the missing two sides of a 45-45-90 right triangle when I know the length of the remaining side.
I can find the length of the missing two sides of a 30-60-90 right triangle when I know the length of the remaining side.
Turn-In (#65)
Txt. p.493 #6-14, 29
Handouts
Chapter 9- Lesson 1: Special Right Triangles
Assignment
Txt. p.493 #15-25, 32, 33
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.
Permalink