Week 7 in Math 10

This week in math we learned how to use trigonometry to find side lengths of right triangles. To start off remember SOH CAH TOA, which means sine=opposite (O)/hypotenuse (H), cosine=adjacent (A)/hypotenuse, tangent= opposite/adjacent. This equation is very important for every trig equation: ratio (reference angle)= side 1/side 2.

So for an example, say you’re given a right angle triangle (example below in picture) and it asks you to find the opposite side (O) the reference angle is 70°, while the hypotenuse is 40m. You would be using sine since you have side H’s length (40m) and you’re trying to find side A. You would plug the numbers into the previously given equation, so it would be, sin 70°= O/40. You can now solve the equation by canceling out 40 on each side leaving you with, 40(sin 70°) = O. So O = 37.6 (rounded)

All you have to do is plug in the appropriate numbers in their respective places and follow the order, 1. label 2. ratio 3. equation 4. solve.

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