1. 5.4 Defining Trigonometric Ratios
Before beginning the activities in 5.4 there are a few terms that must be known.
Trigonometry -

2. 5.4 Defining Trigonometric Ratios
Before beginning the activities in 5.4 there are a few terms that must be known.
Trigonometry – the branch of math that deals with the relationships between the sides and angles of triangles (Usually right triangles. All our trig. will only involve right triangles.)

3. 5.4 Defining Trigonometric Ratios
The sides of a right triangle are given certain names. (You should know one already. The names of the other two depend on the location of the reference angle. The reference angle is simply the angle identified to you or the angle you are trying to determine in a problem.)

4. 5.4 Defining Trigonometric Ratios
Hypotenuse – the side opposite
the right angle
Opposite – the side opposite
the reference angle
reference
angle
Adjacent – the side next to the reference angle (but not the
hypotenuse)

5. 5.4 Defining Trigonometric Ratios
Label the sides of the following triangles. The arrows point to the reference angles.

6. 5.4 Defining Trigonometric Ratios
Label the sides of the following triangles. The arrows point to the reference angles.
A H O

7. 5.4 Defining Trigonometric Ratios
Label the sides of the following triangles. The arrows point to the reference angles.
A H O
H A

8. 5.4 Defining Trigonometric Ratios
Label the sides of the following triangles. The arrows point to the reference angles.
A H O
H A H A

9. 5.4 Defining Trigonometric Ratios

10. 5.4 Defining Trigonometric Ratios
Ratio – a comparison of two (or more) things.
Ex. the ratio of boys to girls in the room is_______

11. 5.4 Defining Trigonometric Ratios
Ratio – a comparison of two (or more) things.
Ex. the ratio of boys to girls in the room is 15 to 10
We often present ratios in 3 ways …..
With colons 15:10
As fractions 15/10
As decimals 1.5