1. 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 a

2. Function name Abbreviation
The three ratios of a right triangle are called trigonometric functions of acute angles and are defined as follows:
Function name
Abbreviation

3. Moving Forward If you don’t get my answers it’s
because your calculator is
not in degrees
Put it in degrees.
If you’re not sure
how to do this, google it!

4. Try these sin (18°) cos (22.7°) tan (11.9 °) sin (84.3°)
0.309
0.923
sin (18°) cos (22.7°)
tan (11.9 °) sin (84.3°)
cos (8.7°) tan (49°)
tan-1 (1.7) sin-1 (0.50)
cos-1 (0.37) cos-1 (0.84)
tan-1 (2.4) sin-1 (0.38)
0.211
0.995
0.988
1.15
59.5°
30.0°
68.3°
32.9°
67.4°
22.3°
On most calculators, the inv is shift or 2nd of the sine, cos or tan
If you’re looking for
sin-1
cos-1
tan-1

5. hypotenuse opposite adjacent
The hypotenuse (hyp) is ALWAYS the side opposite the right angle
The opposite side (opp) is ALWAYS the side opposite angle under consideration
The adjacent side (adj) is ALWAYS the remaining side

6. c = Hypotenuse = 13 b = Opposite = 12 13 12
Find the value of each of the three trigonometric functions of the angle
c = Hypotenuse = 13
b = Opposite = 12 13 12
Adjacent

7. To determine an angle from its sin or cos or tan, use the inv function
You’re looking for
sin-1
cos-1
tan-1
On most calculators, the inv is shift or 2nd of the sine, cos or tan
0.923
Type in
2.4
sin-1 (0.923)
tan-1 (2.4)
cos-1 (0.385)
0.385
67.4°

8. c a b
To solve a right triangle means to find the missing lengths of its sides and the measurements of its angles.

9. hyp c 4
opp b
adj

10. h 25
h = 23.49