Answer:
FD = 8
FE = 21.6
Explanation:
By applying Pythagoras theorem in ΔCDF,
CD² = CF² + FD²
(17)² = (15)² + FD²
289 = 225 + FD²
FD =

=

FD = 8 units
Since AB║DE and CD is a transversal line,
∠BCD ≅ ∠CDF [Alternate interior angles]
m∠CDF = m∠BCD = 55°
By using cosine rule in the right triangle CDE,
cos(55)° =
=

cos(55)° =

EF + 8 =

FE = 29.64 - 8
≈ 21.6 units