Find the length of side x in simplest radical form with a rational denominator

10√3 / 3

Step-by-step explanation:

cos 30 = 5 / x

x = 5 / cos 30

= 5 / √3 / 2

= 10 √3

= 10√3 / 3

Can you upload a picture or something? This is a random problem similar to this.This is just an example

We are given with the data of a parabola with vertex at (2, 2) and directrix at y  = 2.5. the formua should be ax^2 + b x + c = y because of the directrix. 

(x-h)^2 = 4a (y-k)
(x-2)^2 =4a (y-2) 
a is the equidistant distance from focus to vertex and from vertex to directrix that is equal to -0.5
then the  answer is 
(x-2)^2 =-0.5*4 (y-2) 
x2 - 4x + 4 = -2y +4
x2-4x+2y = 0

answer is C