utefdxd的部落格

標題:

f.2 angle in rectilinear

發問:

• Maths~_0
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find the unknown. d圖要向右90度睇. 圖片參考：http://imgcld.yimg.com/8/n/HA00101881/o/701205220035013873407940.jpg 圖片參考：http://imgcld.yimg.com/8/n/HA00101881/o/701205220035013873407941.jpg 圖片參考：http://imgcld.yimg.com/8/n/HA00101881/o/701205220035013873407952.jpg

最佳解答:

1. 圖為四邊形 125? + 50? + 110? + (180? - y) = 360? (angle sum of polygon) 465? - y = 360? y = 105? 2. 圖為六邊形 5c + 90? = 720? (angle sum of polygon) 5c = 630? c = 126? 3. 圖為五邊形 q = 120? (corresponding angles, US // QR) angle UST + angle USR = 180? (adjacent angles on straight line) 120? + angle USR = 180? angle USR = 60? angle USR + angle SRQ + angle RQP + angle QPU + angle PUS = 540? (angle sum of polygon) 60? + 120? + 105? + r + 165? = 540? r = 90?

其他解答:

您好！我是 lop，高興能解答您的問題。 (1) 圖片參考：http://imgcld.yimg.com/8/n/HA01076848/o/701205220035013873407950.jpg ∠EBC + y = 180° (adj. ∠s on st. line) ∠EBC = 180° - y ∠EBC + ∠BCD + ∠CDE + ∠DEB = 180°(4-2) (∠ sum of polygon) 180° - y + 110° + 50° + 125° = 360° y = 105° (2) c + c + c + c + c + 90° = (6-2)180° (∠ sum of polygon) 5c = 720° - 90° c = 126° (3) ∠QRS = ∠UST (corr. ∠s, QR//US) q = 120° 120° + ∠USR = 180° (adj. ∠s on st. line) ∠USR = 60° ∠USR + ∠SRQ + ∠RQP + ∠QPU + ∠PUS = (5-2)180° (∠ sum of polygon) 60° + q + 105° + r + 165° = 540° 120° + r = 210° r = 90°