See screenshot below​

cos theta = -1/ 2

Step-by-step explanation:

sin theta = -sqrt(3)/2

Drawing a triangle

We know sin theta = opp/hyp

We can determine the adj side using the Pythagorean theorem

a^2 + b^2 = c^2

adj^2 + (-sqrt(3))^2 = 2^2

adj^2 +3 = 4

adj^2 = 4-3

adj ^2 =1

Taking the square root of each side

adj = 1

We know that since it is in the third quadrant the adj side is negative

adj = -1

cos theta = adj / hyp

cos theta = -1/ 2

2 2/3 hours duhh silly

step-by-step explanation: