8­2 Day 2 Special Right Triangles 2011
January 31, 2011
8-2 Day 2 Special Right Triangles
Objective:
30
90
60
Use properties of 30-60-90 triangles
to find missing side lengths.
0
Feb 24­1:51 PM
1
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
Check Skills You'll Need
Simplify:
1. (2√2)(3√2)=
2. 4√3(√3)=
3. Find the value of h.
45
h
14
45
Feb 24­1:57 PM
2
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
8-2 Day 2 Special Right Triangles
Objective:
30
90
60
Use properties of 30-60-90 triangles
to find missing side lengths.
Feb 24­1:51 PM
3
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
Draw an equilateral triangle with sides length 2
Draw the altitude
What are the angles?
2
2
2
Feb 24­2:04 PM
4
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
Use the Pythagorean Theorem to find
the lengths of the missing side.
30
x
2
60
Feb 24­2:04 PM
5
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
So why do we care?
In a 30-60-90 triangle the...
30
hypotenuse = short leg x 2
long leg = short leg x √3
2s
s√3
60
90
In other words, the sides in a 30-60-90
s
triangle have a ratio of 1:2:√3
Feb 24­2:04 PM
6
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
Find the lengths of the missing sides.
hypotenuse = short leg x 2
long leg = short leg x √3
Feb 24­2:17 PM
7
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
HOMEWORK
pg. 428 #9-15, 23
Feb 24­2:22 PM
8
8­2 Day 2 Special Right Triangles 2011
January 31, 2011
Jan 30­2:32 PM
9