answer
analyse
Carefully examine the questions, carefully observe the known conditions and given figures in the analysis questions, and solve them according to the judgment and properties of parallel lines and the theorem of triangle internal angle sum.
answer
Solution: AB⊥BC. The reasons are as follows:
∠∠EGF = 30,∠F=90
∴∠feg=90-∠ Epidermal growth factor =90 -30 =60
∠∠FEA = 25
∴∠AEG=∠FEG-∠FEA=60 -25 =35
∠∠EGC = 35
∴∠AEG=∠EGC
∴AD//BC
∠∠A = 90°
∴∠b= 180-∠a = 180-90 = 90
That's AB⊥BC.
So the answer is:
AB⊥BC.
comment
The key to solve this problem is to carefully examine the problem, carefully observe the known conditions and given figures in the analysis problem, and solve it according to the judgment and properties of parallel lines and the theorem of triangle interior angle sum.