Download Section 13-1 Right Triangle Trigonometry Trigonometry

Section 13-1
Right Triangle Trigonometry
Trigonometry - The study of the relationship among angles and the
sides of right triangles.
A
Hypotenuse
C
B
Θ Theta (Shape that means angle)
Sin Θ =
Cos Θ =
Tan Θ =
Some Old Horse Came Across Here To Observe Ants
SOHCAHTOA
New Trig Functions!!!
CSC Θ=
Sec Θ =
CSC=CoSecant (opposite of Sine)
SEC= Secant (opposite of Cosine)
COT=CoTangent (opposite of Tangent)
Cot Θ=
Think about everything needs a CO to make a pair!
Introducing TRIG MAN
Place TRIG MAN at your angle that you need or have.
Examples:
C
Write Six Ratios for Θ
Θ
5
3
B
4
Sin Θ=
Cos Θ=
Tan Θ=
CSC Θ=
Sec Θ=
Cot Θ=
A
SET THE MODE TO DEGREE
Example:
Find x
10
40⁰
X
Example:
Find Θ
10
Θ
14
Angles of Elevation & Depression
Angle of Depression (Looking Down)
38⁰
38⁰ The same degree because of alternate interior angles (Remember Geometry)
Angle of Elevation (Looking up)
NOTICE: The only hard part about this section is interpreting where the
angle is—Remember to ask yourself:
Are you looking up or looking down?
Example:
In a sightseeing boat near the base of the Horseshoe Falls at Niagara Falls, a
passenger estimates the angle of elevation to the top of the falls to be 30⁰. If the
Horseshoe Falls are 177 feet high, what is the distance from the boat to the base
of the falls?
DRAW A PICTURE of a triangle to help solve!
177 ft
30⁰
REMEMBER YOU ARE LOOKING UP!
Homework : TXT p. 706 # 16-26 even,
30-36 even, 42
Class work:
7
8
9