Solving right angle triangles and especially the introduction of sine, cosine and tangent as concept to trigonometry don’t have to be scary. As long as you remember that at this point, you can just understand them as functions in a calculator, then they don’t have to be any more complicated than taking the square root of a number.
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This first practice will have you trying to label the sides of the right angle triangle as either the hypotenuse, the opposite, or the adjacent and then trying to determine whether sin, cos, or tan is the correct trig ratio to use to solve that triangle. If you wanted a refresh, go ahead and watch the video before trying to see a few examples worked out.
The second type of practice once you can determine which trig ratio to use, is actually solving an unknown side of a triangle. In order to solve an unknown side of a right angle triangle you must be given at least two pieces of information. The way you learned in younger grades were you were given two of the sides and used Pythagorean theorem to get the third, or the method you will use here, where you are given an angle and one other side. Watch the video below if you wanted to see some examples worked out. When you feel ready, try some of the practice questions below.
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When you feel ready, try some of the practice questions below. The last type of problem we will solve here, is when we are looking for an unknown angle in a right triangle. Just like when solving for a side, you have to be given two pieces of information. In this case, two different sides. Once you know the two sides, you can choose which trig ratio will give you the correct answer based on SOH CAH TOA. Remember to use your inverse buttons to undo a trig ratio. And don’t forget to be in DEGREE mode. Unless of course you’re solving in radians, in which case, carry on.
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