Write the equation of the parabola with a focus (1,2) and directrix y = 1

Since the y shifted and focus is above directix, parabola opens up
4P(y-k)=(x-h)^2
distance from focus to veretx=distance from vertex to directix=P

from focus to directix is
from 2 to 1 which is 1 distance
1/2=P since 1/2of 1=1/2
4(1/2)(y-k)=(x-h)^2
vertexis 1 higher than directix so add 1/2 to 1 to get 1.5
vertex=(1,1.5)
vertex=(h,k)

equation is
4(1/2)(y-1.5)=(x-1)^2
if you want vertex form
2(y-1.5)=(x-1)^2
divide 2
y-1.5=(1/2)(x-1)^2
add 1.5
y=