Answer:
11.4
Step-by-step explanation:
So we know that Triangle ACB is similar to Triangle EFD.
This means that their sides are proportional to each other.
We want to find x or side AB. To do so, we can set up a proportion.
The proportional side to AB is ED. Let's also use BC since we know its value. The proportional side to BC is DF. Thus:
Substitute x for AB, 3.8 for Ed, 15 for BC, and 5 for DF. Thus:
Reduce the right:
Cross multiply:
So, the value of x is 11.4
And we're done!