So ∠C=∠E ∠BAC=∠DAE.

Because ∠BAC=∠BAD+∠DAC ∠DAE=∠DAC+∠CAE.

So ∠BAD=∠CAE

Because ∠C=∠E ∠DFC=∠AFE

So ∠CDE=∠CAE

So ∠CDE =∠ bud ∠ABD=∠ADB=∠ADE.

(∠ABD=∠ADB because △ABD is an isosceles triangle)

Because ∠ Abd+∠ ADB+∠ Bad = 180, ∠ ADB+∠ Ade+CDE = 180.

So: ∠ CDE =180-∠ ADB-∠ ade =180-∠ Abd-∠ ADB = ∠ bad.