∵AE=AD ∴∠ADE=∠AED ∵∠ADE+∠EDC=∠B+∠BAD=∠B+50° ∠B=∠C ∴∠AED+∠EDC=∠C+50 ∵∠AED=∠EDC+∠C ∴∠EDC+∠C+∠EDC=∠C+50° ∴∠EDC=25°
