Geometry/Notes 7.4
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Transcript of Geometry/Notes 7.4
Section 7.4Trigonometry
Trigonometry• How can I find trigonometric ratios for right
triangles?
Trigonometry• About triangle measurements
• Uses ratios of sides of a triangle to describe an angle
• Sine, Cosine and Tangent
• Abbreviated as sin, cos and tan
Sides• Which side is adjacent to angle B? • Which side is opposite to angle B?• Where is the hypotenuse?
A
BC
c
b
a
Sine
A
BC
c
b
a
Cosine
A
BC
c
b
a
Tangent
A
BC
c
b
a
SOH-CAH-TOA• Memory device
With Numbers!• Find sin, cos, and tan for B
B
AC
135
12
With Numbers!• Find sin, cos and tan for A and B
A
BC
257
24
Homework• Worksheet
Trigonometry• How can I use trigonometry to solve triangle
problems?
Using SOH-CAH-TOA• Calculator • (typically 4 places, round to the nearest ten-
thousandth
• sin 45• cos 36• tan 23
Inverse Functions• Given the trig value, what is the angle measure?
• Inverse function on calculator (
• sin x = 0.8387
• cos x = 0.5000
• tan x = 0.5774
Examples
Example
Application• A plane is one mile above sea level when it begins
to climb at a constant angle of 3° for the next 60 ground miles. About how far above sea level is the plane after its climb?
Application• To guard against a fall, a ladder should make an
angle of 75° or less with the ground.
• A. What is the maximum height that a 20-foot ladder can reach safely?• B. How far from the building is the base of the ladder at
maximum height?
Homework• Worksheet