SOLUTION
In this question, we are meant to find the length of DF.
We should also note that DF = 2 X DH
Next, we also consider that :
DE = 13
EH = 12
DH = ?
Using Pythagoras' theorem,
We have that DE ^2 = EH ^2 + DH ^2
13^2 = 12 ^2 + DH ^2
169 = 144 + DH ^2
169 - 144 = DH^2
DH ^2 = 25
Square- root both sides, we have :
DH = 5
Note: DF = 2 X DH
DF = 2 X 5
DF = 10