1. HMWK: p. 554, #s 12 – 25 all
Game Plan: Today I will be able to use special right triangles to calculate side lengths.
Warm-up: Simplify the following radicals. Leave in radical form.

2. Special Right Triangles
Isosceles rt. triangle with angles measures of 45°, 45°, and 90°
Ratio of the length of the sides is 1 : 1 : 2
Corresponds to leg : leg : hypotenuse

3. 45-45-90 Example Find the missing length of the side x.
leg=x, hyp.=2 legs=6, hyp.=x

4. Special Right Triangles
Rt. triangle with 30°, 60°, 90° angles
Ratio of side lengths is 1 : 3 : 2
Corresponds to short leg : long leg : hypotenuse

5. Examples
Find the missing lengths of the sides.

6. Applications
The roof of a doghouse is shaped like an equilateral triangle with height 3 feet. Estimate the area of the cross-section of the roof.
Steps
Use spec. tri. relationships to find base of triangle
Use area formula
3 ft
5.2 ft.

7. Wrap-Up
What do we use the special right triangle relationships to determine?
State the ratio ratio.
Will begin trig ratios tomorrow – NEED CALCULATORS!!!