Transcript Sect9-1-2 - epawelka-math

Section 9-1/9-2:
Trigonometric Ratios
April 16, 2012
Warm-up: (15 mins)
Sections 9-1/9-2
Trigonometric Ratios
Objective: Today you will learn to find
sine, cosine and tangent ratios for acute
angles of right triangles.
Trigger Fish: “Trig”
Tang: “Tangent”
Investigation
Right Triangles: sides and angles
Draw right triangles with your assigned m∠A:
Measure the sides (in cm) of each triangle and fill in this chart:
Investigation
Right Triangles: sides and angles
Trigonometric Ratios: Sine
Trigonometric Ratios: Cosine
Trigonometric Ratios: Tangent
Trigonometric Ratios: Sine/Cosine/Tangent
“SOH CAH TOA”
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Happily to Other Adventures
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Make up your own!
Trauma On Accidents
Example 1:
Find the following ratios for this triangle
Leave in fraction form.
Example 2:
Find sine, cosine, and tangent of angles A and B in
each right triangle. Leave in fraction form.
Using your Calculator
First ensure the calculators are set to use degrees for angles:
Using your Calculator
Example 3: Find missing side
Example 4: Find missing sides. Round to
nearest tenth.
Inverse Functions
To find the measure of angles
given sides, use the inverse
functions:
• sin-1
• cos-1
• tan-1
Example 5:
Find m∠x to the nearest whole number
Example 6: Find missing angle
measurements to the nearest whole number
Unit Circle
Hypotenuse = 1, so
Sin(angle) = y
Cos(angle) = x
Tan(angle) =
y
x
Wrap-up
Today you learned to find sine, cosine and tangent ratios for
acute angles of right triangles.
Tomorrow you’ll learn to identify the angle of elevation and
depression and use them with trigonometric ratios.
Homework (H)
 p. 472, # 1-16, 27 - 29
 p. 479, # 1-17, 22 -25
Homework (R)
 p. 472, # 1-16, 28
 p. 479, # 1-17, 24