正方形ABCD中,F是AD的中点
CAN YOU UNDERSTAND THE ENGLISH?
because I am in oversea。I am in school so I can not type in Chinese!
but keep in mind try to understand me。
1。ABCD is 正方形,so let AB=1 so the AF is 1/2 so to make a line from F to BC to be the vertical line。 the point of the line occour the AC line from F is the O...全部
CAN YOU UNDERSTAND THE ENGLISH?
because I am in oversea。I am in school so I can not type in Chinese!
but keep in mind try to understand me。
1。ABCD is 正方形,so let AB=1 so the AF is 1/2 so to make a line from F to BC to be the vertical line。
the point of the line occour the AC line from F is the O。
2。 the 面积 of the DCOF is [(1/2+1)*1/2]/2=3/8 but the 面积 of the CGFD have to including the 三角形 FOG so 。
。。。。。
3。 prove the 三角形ABG is similar to the 三角形FDG
and the line FO is the vertical to the line BC so AB//FD then prove they are similar so 三角形ABG 与 三角形FDG 面积之比 is 2:1 so the 三角形FDG is (1/2*1/6)/2=1/24。
。。。。。。。so the 四边形CGFD的面积is 3/8+1/24=5/12
then that is easy to work out the answer of the 三角形BGC, so that is the answer。
。收起
