Answer: D) 49 degrees
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Work Shown:
You'll need to use a trig ratio. Specifically, we'll be using cosine here
cos(angle) = adjacent/hypotenuse
cos(x) = 13/20
cos(x) = 0.65
x = arccos(0.65)
x = 49.4583981264954 which is approximate
x = 49
The missing angle is approximately 49 degrees
Make sure your calculator is in degree mode. The notation arccos refers to arccosine and it's the same as inverse sine.
