Answer:
83.5units
Step-by-step explanation:
Find the diagram attached
Since both triangles are similar, then;
AB/DB = BC/EF
11/54 = 17/EF
Cross multiply
11EF = 17 * 54
11EF = 918
EF = 918/11
EF = 83.5
Hence the length of EF to the nearest tenth is 83.5units