<u>answer:</u> 
<u>work:</u>
| subtract 13.50 and move it over
| divide by 7/2
| final answer
Answer:
A C and E
Step-by-step explanation:
That is a 30 60 90 triangle
The "short" side (DE) equals the middle side (FE) times (1 / sq rt(3))
short side = 8 * sqrt(3) * (1 / sq rt(3) = 8
Hypotenuse (DF) is 2 times the short side which equals 16.
Source:
http://www.1728.org/trig2.htm