hi Dan. do you mean (243+234)/(52+54)? i don't know how you get 4.5 by multiplying. if that's so, then maybe:
=SUMIFS(C:C,A:A,F2,B:B,G2)/SUMIFS(D:D,A:A,F2,B:B,G2)

assumption:
F2 is:
19Dec2013
G2:
10 am