Find the vertex, focus, directrix, and focal width of the parabola.

x2 = 20y

Directrix is line with equation y=-5 and focus is the point with coordinates (0,5) with vertex (0,0) and focal width 20 units.

Step-by-step explanation:

Given the equation of parabola i.e

we have to find the vertex, focus, directrix, and focal width of the parabola.  

Parabola:  

Comparing, we get

⇒

Vertex: (0,0)

Focus: (0,b)=(0,5)

Directrix: y=-b ⇒ y=-5

Focal width:  4(5) = 20 units

Directrix is line with equation y=-5 and focus is the point with coordinates (0,5) with vertex (0,0) and focal width 20 units.

answer

d. 10

explanation

the distance from point y to wx is the height of the triangle.

using pythagoras theorem,

group similar terms to get,

this implies that,

take positive square root of both sides to get,

this implies that,