a set of the proportion that will find the missing side of the following pair of similar triangles

From the information given, triangle ABC is similar to triangle DEC
This means that
AB/DE = BC/EC = AC/DC
Given that AB = 3, BC = 4 and CE = 14, it means that
3/DE = 4/14
By cross multiplying, it becomes
3 * 14 = 4 * DE
42 = 4DE
DE = 42/4
DE = 10.5