Download Geometry

Trigonometric Ratios
Geometry
Click here to find out
WHAT IS TRIGONOMETRY?
Things to know
The following sides are
labeled in regards to the
angle . It is important to
know that the location of
the opposite and adjacent
sides will change
(depending on the angle),
but the hypotenuse will
always be the same!
TRIGONOMETRIC RATIO
A trig ratio is a ratio of the lengths of two sides
of a right triangle. There are three basic trig
ratios:
sine
sin
cosine
cos
tangent
tan
Trig Ratios
Trigonometric ratios are frequently expressed as
decimal approximations.
• You should round the trig ratio to the
ten-thousandths place.
What are the 3 trig ratios?
SINE
COSINE
TANGENT
Find sin, cos, and tan of A
A
z
x
B
y
C
Example
Compare the sine, the cosine, and the tangent
ratios for angle A in each triangle below.
B
B
13
5
6.5
2.5
C
12
A
C
6
A
Example
Find the sine, the cosine, and the tangent of
angle D and angle E.
E
50
14
F
48
D
Use A Calculator
Use a calculator to approximate the sine,
cosine, and tangent of 82 degrees.
Use a Calculator
Use a calculator to approximate the sine,
cosine, and tangent of 54 degrees.
Note:
Sin and Cos must always be less than 1!!