Question

Please help! If sin Θ = 3 over 7 and tan Θ < 0, what is the value of cos Θ?

Answer 1

Since \[\sin \Theta = \frac{ opposite }{ hypotenuse }\] \[\cos \Theta = \frac{ adjacent }{ hypotenuse }\] \[\tan \Theta = \frac{ opposite }{ adjacent }\]
you can draw the triangle:



Then you can use Pythagorean theorem to find the adjacent side and therefore the cosine