Inside Angle = 140

送交者: 零加一中 2020月03月16日07:57:10 于 [灵机一动] 发送悄悄话

回  答: 趣味的数学-282 由 gugeren 于 2020-03-13 18:55:41

Sum of inside angle = 7 X 180. Inside angle = 140. a and b has angle 20. a cos 20 = b/2 b and d has angle 50. b cos 50 = d/2

0%(0)

对！是a+b=d　/无内容 - gugeren 03/16/20 (161)

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