In the figure, ∠BCD=100°, ∠ABD=70° and ∠ADB=x. Find x.
*** don't use the reason "opp. ∠s, cyclic quad."
圖片參考：http://imgcld.yimg.com/8/n/HA00215765/o/701104160111113873427430.jpg
properties of circles x1
2011-04-17 4:21 am
回答 (1)
2011-04-17 4:50 am
✔ 最佳答案
Join AC ,ㄥACD = ㄥABD = 70° (ㄥS in the same segment)ㄥACB = 100° - ㄥACD = 100 - 70 = 30°x = ㄥACB = 30° (ㄥS in the same segment)
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