Because △EFB and △GDB are right triangles, ∠DGB=∠CED,
∠ EDC =∠ GDB = 90 degrees, DC = decibel.
So △ EDC △ GDB = > ED=GD
Because AD=CD and AE=CG.
(2) Because BE=BD+DE=CD+DE, the line segment equal to it may be CM.
That is, it is necessary to prove that DM=DE.
Because ∠AEH=∠CED, ∠ AHE = ∠ CDE = 90.
So ∠ DCE = ∠ EAH = > ∠DCE =∠ dam
At △ADM and △CDE:
∠ADM=∠CDE=90
∠DCE =∠ dam
AD=CD
So △ ADM△ CDE
So DM=DE
So CM=BE