Since the argument of the sine function is x without any scaling factor, the period is 2π, the 1st selection.
Can u make a graaph showing this
The slope is 5/3 and the y- intercept is -2/3
For this question, we're going to use the law of cosines.
The law of cosines is the following equation:

We know the values of a, b, and c. We want to find the measure of angle A.



Now, plug in these values into the equation.


Add both sides by

and subtract both sides by 16

Divide both sides by 36

Take the inverse cosine, or arc cosine, of both sides.
Using a calculator, you'll get the following result.

The measure of angle A should be 36.3 degrees. Hope this helps! :)
Ok, the perimeter of the rectangle is 40 inches.