Answer:
The answer to your question is x = 12
Explanation:
Data
BC = 7
DE = x
AB = 7
BD = 5
Process
To solve this problem use proportions and cross multiplication. Compare the ΔADE and ΔABC.
DE / (AB + BD) = BC / AB
-Solve for DE
DE = BC (AB + BD) / AB
-Substitution
DE = 7(7 + 5) / 7
-Simplification
DE = 7(12) / 7
DE = 84/7
-Result
DE = 12