Download 7-2 Right Triangle Trigonometry

7-2 Right Triangle Trigonometry
Pull out those calculators!!!
What? Did I read that right?
Yes – we will be using calculators now. You
may use either a graphing calculator or
scientific calculator. The only thing is that
you must make sure you know how to
use the calculator. If you don’t, see me
TODAY!!
Don’t get too excited. You have to know how
to put it into the calculator after correctly
interpreting the information.
Absolutes
1. Make sure the calculator is in degrees
Scientific: Press DRG button till you see DEG
on the face
Graphing: Mode then toggle down and toggle
left/right to degrees
2. Make sure you know how to find
sin/cos/tan of angles
Scientific: put in number, then press function
Graphing: Function, number, enter
Absolutes
3. If you have a sine or cosine value and
want to find the angle, you will use sin-1
or cos-1. These are the inverse functions.
Remember the definition of inverse: Put in the
answer, get out the original (angle)
Everything will be based on the triangle
shown below. As it is called “Right
Triangle Trig” you can assume there is a
right angle. We will always have the right
angle in the same place.
B
c
A
a
b
C
Note: B = 42 means angle B = 42.
Examples
ΔABC is a right triangle with C = 90. Solve
for the indicated part(s).
1. A = 42, b = 4; c = ?
2. b = 4, c = 7; B = ?
Word Problems
sorry Monica
Before we do this, you need to understand 2
standard phrases:
Angle of Elevation: Angle rising from
horizontal
Angle of Depression: Angle dropping from
horizontal
Examples
3. How tall is a tree whose shadow is 47 feet
long when the angle of elevation is 49.3
4. One of the equal sides of an isosceles
triangle is 23 cm and the vertex angle is
43. How long is the base?
Examples
5. A balloon is floating between 2 people
who are 50 feet apart. The angle of
elevation of balloon is 63.5 from person A
and 32.6 from person B. How high up in
the air is the balloon?