Question

DEFIf E is a midpoint of DF and DF = 780 then find EF.

Answer 1

We have the following picture

By midpoint, it means that the distance from E to D is the same distance from E to F. So, DE = EF. If means that if the distance from D to F is 780, the distance from D to E is exactly the half of the distance from D to F. So the distance from DE is 780/2 = 390. Since EF=DE, we get that EF = 390.