In the diagram, triangle ABE, triangle BCE and triangle CDE are right-angled, with Angle AEB= Angle BEC= Angle CED=60 degrees, and AE=25. Find the length of DE.
AE = 25
BE = 25(cos60) = 12.5
CE = 12.5(cos60) = 6.25
DE = 6.25(cos60) = 3.125 or 31/8
