問題詳情:
如圖4244所示的鋼架中,焊上等長的13根鋼條來加固鋼架.若AP1=P1P2=P2P3=…=P13P14=P14A,則∠A的度數是__________.
【回答】
12° 解析:設∠A=x.∵AP1=P1P2=P2P3=…=P13P14=P14A,∴∠A=∠AP2P1=∠AP13P14=x.∴∠P2P1P3=∠P13P14P12=2x,∴∠P3P2P4=∠P12P13P11=3x,…,∠P7P6P8=∠P8P9P7=7x,∴∠AP7P8=7x,∠AP8P7=7x,在△AP7P8中,∠A+∠AP7P8+∠AP8P7=180°,即x+7x+7x=180°,∴x=12°.即∠A=12°.
知識點:等腰三角形
題型:填空題