Answer:
Since the focus is at (-6,-11) and the directrix is at y=9:
The vertex is halfway between the focus and the directrix, so the vertex is at (-6,-1). (Draw this on graph paper if that doesn't make sense.)
The general form (conics form) of a parabola: 4p(y-k)=(x-h)^2 (vertex is (h,k) and "p" is the distance between the focus and vertex (or between vertex and directrix)).
(h,k) = (-6,-1)
p = 10 (distance between focus and vertex), so 4p = 40.
Therefore:
40(y+1)=(x+6)^2
Or if you need to rearrange to "vertex form": y=(1/40)(x+6)^2 - 1
Step-by-step explanation:
37.01 for Jayna.
36.91 for Myriam.
36.78 for Riley.
How many males and how many females would there be if the total enrollment is 15000?
Ratio is
90 males 15000 - x
------------- = ---------------
125 fem x
Then 90x = 1875000 - 125x, or 215x = 1875000
x = approx 8720 females
and 15000-8720, or 6279 males
If every male finds a dance partner, that would leave (8720-6279) females, or 2440, without dance partners. ;(
Check: is the male:female ratio near 90:125?
Is 6279:8720 approx equal to 90:125?
Yes. 0.72 (approx) = 0.72 (approx).
An isosceles triangle is one having two of its sides equal.
