Final answer:
To find the ratio of the length of DF to the length of DE, substitute the given values of DE and DF into the ratio formula and calculate the ratio.
Step-by-step explanation:
To find the ratio of the length of DF to the length of DE, we need to substitute the given values of DE and DF into the ratio formula.
DE = 3e + 6f
DF = -10.5e-21f
Now we can calculate the ratio:
Ratio = DF / DE
Ratio = (-10.5e-21f) / (3e + 6f)
Ratio = -10.5e-21f / (3e + 6f)