-------------------------36.06
Divide the quantity done by the time:
2/3 / 3/4
When dividing by a fraction flip it over and change divide to multiply:
2/3 x 4/3 = (2 x4) / (3x 3) = 8/9
In 1 hour she will complete 8/9 of the project.
If the value of cos(θ) is negative, this angle (θ) can only be in one of two quadrants; the sine quadrant or the tan quadrant. In the sine quadrant, tan(θ) must be negative, but since tan(θ) > 0, we can safely say that the angle (<span>θ) is based in the tan quadrant.
We know that cos(</span><span>θ) = - Adjacent / Hypotenuse, and in this case Adjacent = 2 and Hypotenuse = 5. Using Pythagoras' theorem, we can find the opposite side of the right angled triangle situated in the tan quadrant...
</span>Adjacent² + Opposite² = Hypotenuse²
Therefore:
2² + Opposite² = 5²
Opposite² = 5² - 2²
Opposite² = 21
Opposite = √(21)
------------
Now, sin(θ) must be negative, as the right angled triangle is in the tan quadrant. We also know that sin(<span>θ) = Opposite / Hypotenuse, therefore:
sin(</span><span>θ) = - [</span>√(21)]/[5]
