there are three rules for significant numbers
all non zero digits i.e 1,2,3,4,5,6,7,8,9 are always significant.
all or Any zero in between 2 significant digits or numbers are significant.
trailing zeros or final zero in the decimal part are considered significant.
According to the rules of significant figures( described above), the zeros after the decimal point are significant hence 54289.00 has seven significant figures instead of five.