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Lesson 9.10 - Trigonometric Ratios

Today, we continued to look at how to use the Trigonometric ratios in different types of problems. The most important type for now is how to find the measure of an angle, given the appropriate sides. For example, look at the following problem:

Trig example problem

How did we find the measure of angle A? We started by figuring out that the Sin A (opp/hyp) = .5572. From here, we could do one of two things - look up that value in the Trig Ratios Values chart (on page 424 of the book) to see what the closest angle is, or by taking the inverse sine (or arcsine) of the value by using the appropriate button on our calculators. With this information, we are able to "Solve the rest of the right triangle" by finding e (could you also find angle B?).

Trig example 2

That's it for trig for this'll get plenty more next year and during your junior year! For now, you should be able to "solve a right triangle" given any two of its parts.

Other Links
Class Notes
Lesson 9-1
Lesson 9-2
Lesson 9-3
Lesson 9-4
Quiz Topics
Lesson 9-5
Lesson 9-6
Lesson 9-7
Lesson 9-8
Lesson 9-9
Lesson 9-10
Test Topics
Trig Table
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