IndexError: list assignment index out of range

[Apretext]

This seems to be something that a lot of new people to python seem to struggle with, and I'm no exception....

I understand that appending the values is something I need to do, but.. I'm obviously not doing it QUITE right..

This is my code:

x=0
dist=[]
while x < 100:
dist.append(x)
dist[x]=400/(math.cos(angle))
print (dist[x])
x = x+1

Where angle comes from earlier in the code. But I still get the list assignment out of range error. What am I doing wrong?