Download Lesson 4 – The Sine Ratio – Measure

WA10 – Unit 7 – Trigonometry of Right Triangles
Lesson 4 – The Sine Ratio - Measure
Date: _______________
Lesson 4: The Sine Ratio - Measure
Finding the Measure of an Angle Using Sin
1) Determine your values of opposite, adjacent, and hypotenuse
2) Substitute values into ratios
3) Find ratio as a decimal
4) Use
sin 1
to find the measure of the angle.
Example 1: In  DEF, identify the side opposite  D and the side adjacent to  D. Determine
the measure of your angles using the Sine Ratio
Example 2: Find the measures of an angle using the Sine ratio
Angle of Elevation – The angle formed between the horizontal and the line of sight when
looking upward.
Angle of depression – the angle formed between the horizontal and the line of sight when
looking down.
WA10 – Unit 7 – Trigonometry of Right Triangles
Lesson 4 – The Sine Ratio - Measure
Date: _______________
Worksheet 4
1. Find the Sine Ratio and the measure of the angle
A
5
4
C
B
2. Find the Sine Ratio and the measure of the angle
J
G
4
10
H
2. You are building a ramp that has a length of 15 ft. The ramp is raised 3 ft off the ground. What is the
angle of elevation?
3. You are flying in a plane at an altitude of 3000 ft. You know that the spot you want to land is 4000 ft
away on a horizontal distance. The plane has to travel 5000 ft to the destination. What is the angle of
depression that the plane should take?
4. Determine the angle for the following:
a) sin A = 0.5491
b) sin A = 0.2412
c) sin A = 0.2323
5. Find the indicated angle:
a)
b)
12.4 cm
x
8.9 cm
7.9 cm
x
6.2 cm
c) sin A = 0.5