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如圖,∵將紙片△ABC沿DE折疊,點A落在A′處,∴∠3=∠4,∠5=∠6,而∠1+∠3+∠4=180°,∠2+∠5+∠6=180°,∴∠1+∠2+2∠3+2∠5=360°,而∠1+∠2=150°,∴∠3+∠5=105°,∴∠A=180°-∠3-∠5=75°.故答案為:75°.
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