標題:
f.4 circle
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發問:
1)http://i729.photobucket.com/albums/ww291/kaka1307/DSC00530.jpgtwo circles meet at A & C.ABK is a straight line and angle ABC=130.Find a)angle AOCb)angle CKB2) http://i729.photobucket.com/albums/ww291/kaka1307/DSC00531.jpgCB is the diameter of the circle CBD,CBA and CDE are straight lines.If angle... 顯示更多 1) http://i729.photobucket.com/albums/ww291/kaka1307/DSC00530.jpg two circles meet at A & C.ABK is a straight line and angle ABC=130. Find a)angle AOC b)angle CKB 2) http://i729.photobucket.com/albums/ww291/kaka1307/DSC00531.jpg CB is the diameter of the circle CBD,CBA and CDE are straight lines. If angle BCD=35,find angle AEC. pls show steps.thz!
最佳解答:
1)a) 360 - ㄥAOC = 2ㄥABC (圓心角兩倍於圓周角) 360 - ㄥAOC = 2 * 130 ㄥAOC = 100° b) ㄥAOC + ㄥCKB = 180 (圓內接4邊形對角互補) 100 + ㄥCKB = 180 ㄥCKB = 80° 2) Join BD , ㄥABC = ㄥCBD (圓內接4邊形對角之補角) ㄥBDC = 90° (半圓所對圓周角) So ㄥABC = ㄥCBD = 180 - 35 - ㄥBDC = 180 - 35 - 90 = 55° 2010-05-13 18:11:53 補充： 003 H ( 小學級 3 級 ) 抄答案!! 立即檢舉!!!!
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