有一條數唔識做

ctk0907

鉛筆痕唔好理  我fd畫的

§阿虛§

原來我同你用埋同一本書...
本書個 hints 俾左哩個圖....
佢寫住...

As shown in the figure, we can obtain y - x = -10 度 by using the fact that the sum of abjacent angles at a point is 360 度. Hence, we can find <AOB....

我諗睇完哩段野之後應該識做了...

L.K.

um...
有冇學過INCENTRE?

§阿虛§

um...
有冇學過INCENTRE?
L.K. 發表於 10-4-2009 00:49

妙 ! 妙 ! 妙 ! 極快的方法 [[onion_46]]

好精彩的 tangent properties..... [[onion_56]] (是 tangent properties 吧？ =.=)
incentre 有 properties 可以應用到0係哩題？ [[onion_54]]
好想知啊 /口\

L.K.

incentre都係用黎證兩個角相等..
同TANGENT PROPERTIES冇分別
http://en.wikipedia.org/wiki/Triangle

§阿虛§

咦 =.=
係喎 = =
個 incentre 係 angle bisector 0既交點黎 =.=

但係...quadrilateral 用到？只要係 inscribed, 唔係triangle 都得？

L.K.

未一樣=.=''
廷長D線未三角形LOR

§阿虛§

係喎 =.=
咁都得 =.=
咁姐係哩樣野適用於任何 inscribed circle =0=

ctk0907

原來我同你用埋同一本書...
本書個 hints 俾左哩個圖....
佢寫住...

As shown in the figure, we can obtain y - x = -10 度 by using the fact that the sum of abjacent angles at a point is 360 度. Hence, we  ...
§阿虛§ 發表於 10-4-2009 00:17

條數係我個fd比我計- -

um...
有冇學過INCENTRE?
L.K. 發表於 10-4-2009 00:49

有學過但唔記得左
介唔介意講述比我聽  plz~

L.K.

一個3角形..
3條角平分線相交果一點就係incentre
起3角形入面畫一個最大ge圓形
圓心=incentre
http://en.wikipedia.org/wiki/Triangle
呢到有齊哂..