∠∠ ade = 90 ∠∠∠ ADB and ∠∠ ∠EDF are complementary angles ∴∠∠ ADB =∠ def.
* ad = Germany ∴△ABD≌△DFE
∴DF=AB iron =BD
∫ab = BC ∴df=bc ∴df-dc=bc-dc, which means CF=BD.
∴CF=FE ∴△CFE is an isosceles right triangle ∴∠ECF=45.
∴∠BCE= 135