HolcombMath

Tuesday, April 14, 2009

Geometry (Class 68)

Announcements
Test Friday focusing on completing the square, special right triangles, and using right triangles.

Lesson Title
Special Right Triangles (2)

Overview
The opener for today focuses on developing fluency with solving quadratic equations by completing the square. The lesson for the day starts with some review and practice related to 45-45-90 triangles and finding the length of the hypotenuse when the length of the side is knows or conversely finding the length of a side when the length of the hypotenuse is known. We then move on to look at the second type of special right triangle-- triangles which are half of an equilateral triangle.
Textbook Sections
§9.4 (Txt. p.551) Special Right Triangles

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 (#67)
No Homework

Handouts
No Handouts Posted

Assignment
Txt. p.554 #12-17, 21, 22, 24
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.