<span>Simple. The two cyclists have covered a distance of 39 miles in 1.5 hours. 39 divided by 1.5 = 26, so 26kph combined speed. Then just divide 26 by 2 = 13kph, which is the average speed of each cyclist. Then add 2kph to the one cyclist and subtract 2kph from the other. One is going at 15kph, the other is going at 11kph. </span>
So you need to use the inverse tan to find the measure of angle c.
So since tan is opposite over adjacent.
You get the inverse tan of 6/8. And you get 36.87 degrees.
X=12, y=7.5
Here is an explanation if you want to know how to do it:
First, look at the diagram and think about what you know so far. Since the lines are parallel, 5x+4y and 12y must be equal. We also know that there is a right angle, so since both angles are equal, 12y=90 and 5x+4y=90.
Solve for y by dividing 90 by 12 to get 7.5, so y=7.5. Sub in this value to the equation on top and you should get 5x+4(7.5)=90 4(7.5)=30, so subtract that from 90 to get 60 and divide 60 by 5 to get 12, so x=12.
Number one is none of them
Given that the directrix is at y = 4 and the focus is at (0, -4), then the vertex is at (h, k) = (0, 0).
p is the distance between the vertex and the focus and between the vertex and the directrix = 4 and since the focus is below the directrix, p is negative, i.e. p = -4
Equation of a parabola is given by (x - h)^2 = 4p(y - k)
Therefore, the required equation is (x - 0)^2 = 4(-4)(y - 0)
x^2 = -16y
y = -1/16 x^2
