Trigonometry
A Guide to Right Triangles, Trigonometric Ratios, and
Angles of Elevation and Depression
,TABLE OF CONTENTS
1 RIGHT TRIANGLES
2 THE PYTHAGOREAN THEOREM
SPECIAL RIGHT TRIANGLES
3
4 PYTHAGOREAN TRIPLES
5 TRIGONOMETRIC RATIOS
6 RECIPROCAL TRIGONOMETRIC RATIOS
7 COFUNCTION IDENTITIES
7
8 TRIGONOMETRIC RATIOS OF SPECIAL
ANGLES
9 SOLVING RIGHT TRIANGLES
7
10 ANGLES OF ELEVATION AND DEPRESSION
7
11 REVIEW EXERCISES
, Right Triangle
A right triangle is a triangle that contains one 90° angle. The two sides that form the right
angle are called the legs, and the side opposite the right angle is called the hypotenuse.
The hypotenuse is always the longest side of a right triangle.
B
Hyp
ote
nu
Leg
se
A C
Leg
Pythagorean Theorem
The Pythagorean Theorem states that in a right triangle, the square of the hypotenuse is
equal to the sum of the squares of the other two sides.
M
If a and b represent the legs and
represents the hypotenuse, then:
L N