Download Pre-Calc Midterm Study Guide Units 1

6-1 Right Triangle Trigonometry
Objectives: 1.
2.
3.
4.
Define the 6 trig ratios of an acute angle in terms of a right triangle.
Evaluate trig ratios.
Use inverse trig ratios to find missing angles.
Practice using a calculator to find angles and ratios.
The Six Trig Ratios
They relate an acute angle in a right triangle to a ratio of sides
SOH-CAH-TOA
30°
3
2
Th
60°
1
Sin 30°
Csc 30°
Cos 30°
Sec 30°
Tan 30°
Cot 30°
Sin 60°
Csc 60°
Cos 60°
Sec 60°
Tan 60°
Cot 60°
Example: Use the trig ratios to find . Do not use a calculator. Draw a sketch.
1.
sin  
1
2
2. cos  
3
2
3. tan   3
Example: Use a calculator. Round your answer to 4 decimal digits. When you use right triangle trigonometry,
put your calculator in degree mode, unless there is a π with the angle.
1.
sin 65° =
2. cos 19° =
3. tan 23° =
4.
csc 77° =
5. sec 58° =
6. cot 11° =
Inverse Trig Ratios – used to find the missing angle when you know the ratio of sides of a
right triangle
Example: Find . Use a Calculator
1.
sin  = ¼
4. csc  = -4
2. tan  = 2
3. sec  = 8
5. cot  = 1/3
6. cos  = -7/8