Download 8.2 Right Triangle Trigonometry - Parkway C-2

13.1 Right Triangle Trigonometry
• Trigonometry: The study of the properties
of triangles and trigonometric functions and
their applications.
• Trigonometric ratio: A ratio of the
measures of two sides of a right triangle is
called a trigonometric ratio.
The six ratios of a right triangle are called
trigonometric functions of acute angles and are
defined as follows:
Function name
Abbreviation
Value
A triangle in which one angle is a right angle is
called a right triangle. The side opposite the
right angle is called the hypotenuse, and the
remaining two sides are called the legs of the
triangle.
c
b

90
a
opposite
opposite
b
sin  

hypotenuse c
adjacent
a
cos 

hypotenuse c
opposite b
tan  

adjacent a

adjacent
c
b

a
opposite
hypotenuse c
csc  

opposite
b
hypotenuse c
sec  

adjacent
a
adjacent a
cot  

opposite b

adjacent
c
b

a
Find the value of each of the six trigonometric
functions of the angle 
c = Hypotenuse = 13
12
13
Adjacent
b = Opposite = 12
a  Adjacent = 5
b  Opposite = 12
c  Hypotenuse = 13

c
a

b
To solve a right triangle means to
find the missing lengths of its sides
and the measurements of its angles.

c
4

35
b
h
25

70
h = 23.49