∠C=58°
∵ab=ac
∴∠B=∠C
∵∠B=∠C,bd=cf,be=cd
∴△BDE≌△CFD
∴∠CFD=∠BDE
∵∠CDF+∠FDE+∠BDE=180°=∠C+∠CDF+∠CFD
∴∠C=∠FDE=58°