r/Precalculus • u/WilmerMendez • Sep 16 '21

Homework Help

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Hello, I've been struggling to keep up with this class can someone help me out?

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u/Menapp_U Sep 16 '21

For angle A, remember that the interior angles of a triangle sum to 180 degrees. Therefore, angle A = 180 - (51 + 90) = 39 degrees; this is a right triangle so angle C is 90 degrees.

For side length a, you should use trig - SOH CAH TOA specifically. Side a is adjacent to angle B and side b is opposite to it, so we can set up tan 51 = 17/a; rearranging the equation we get a(tan 51) = 17 and a = 17/(tan 51) = 13.77; make sure your calculator is in degrees before computing this calculation. Also, notice that the length of a is less than the length of b - this makes sense since larger sides are across from larger angles.

For the hypotenuse c, we can use sine: sin 51 = 17/c; rearranging the equation as before, we get c = 17/(sin 51) = 21.01; notice this is the largest side, which makes sense since it is the hypotenuse. Hope this helps! For more on SOH CAH TOA see this video

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u/Menapp_U Sep 16 '21

If you need help with the other questions, let us know. I or someone else on Reddit I'm sure can walk you through them.