∴BC=BA

Angle DEB=60 degrees, angle DEB= angle DCE ten decks.

Angle DCE=30 degrees = angle DEC

∴DC=DE=20,BD= 10

Angle BDE=60 degrees

∴BE= 10√3

∴BC=BA=DC+CB=30

∴AE = a B- be = 30- 17.3 = 12.7m