The calculations are incorrect because the angles in a parallelogram are either:
The same
or complimentary (add up to 180)
Neither case is true here so the calculations are incorrect.
Remember that cos is just a translation of sin and vice versa.
So:
Sin(x) = Cos(90 - x)
Cos(x) = Sin(90 - x)
Therefore, to answer your question:
Cos(19) = Sin(90 - 19)
= Sin(71)
To find an inverse, switch the x and the y and solve for the new y. Yours switched is x = 3y. Now solving for y we divide both sides by 3 to get y = x/3
Answer:
6 is the area of a parallelogram
