∫ Advertising Sharing ∠BAC ∴∠DAC=∠DAE

∴∠EDA=∠DAE, △ADE is an isosceles triangle.

There are ∵EF⊥AD and ∴EF vertical sub-advertisements.

∴FA=FD∴∠FAD=∠FDA

∫, ∠ FAD = ∠ FAC+∠ DAC, ∠FDA=∠B+∠DAE and ∠DAC=∠DAE.

∴∠FAC=∠B