鍖楀笀澶х増锛屽垵涓夛紝涔濆勾绾ф暟瀛︽暟瀛︿笂鍐岋紝璇惧悗涔犻绛旀
绗?/p>
4
椤电粌涔犵瓟妗?/p>
瑙ｏ細鍥犱负鍦ㄨ彵褰?/p>
ABCD
涓紝
AC卤
BD
浜庣偣
O
锛屾墍浠モ垹
AOB=90掳
.
鍦?/p>
Rt
鈻?/p>
ABO
涓紝
OB=鈭?AB^2
-
AO^2 )=鈭?5^2
-4^2 )=3
锛?/p>
cm
锛?/p>
.
鍥犱负鍦ㄨ彵褰?/p>
ABCD
涓紝瀵硅绾?/p>
AC
锛?/p>
BD
浜掔浉骞冲垎锛屾墍浠?/p>
BD=2OB=6cm.
1.1
1.
璇佹槑锛氣埖鍥涜竟褰?/p>
ABCD
鏄彵褰紝鈭?/p>
BC=AB,BC//AD,
鈭粹垹
B+
鈭?/p>
BAD=180掳
锛堜袱鐩寸嚎骞宠锛屽悓鏃?
鍐呰浜掕ˉ锛?/p>
.
鈭碘垹
BAD=2
鈭?/p>
B,
鈭粹垹
B+2
鈭?/p>
B=180掳
锛屸埓鈭?/p>
B=60掳
鈭?/p>
BC=AB
锛?/p>
鈭粹柍
ABC
鏄瓑杈逛笁瑙掑舰锛堟湁涓�涓涓?/p>
60掳
鐨勭瓑鑵颁笁瑙掑舰鐨勭瓑杈逛笁瑙掑舰锛?/p>
.
2.
瑙ｏ細鈭靛洓杈瑰舰
ABCD
鏄彵褰紝鈭?/p>
AD=DC=CB=BA,
鈭?/p>
AC卤
BD,AO=1/2 AC= 1/2脳
8=4
锛?/p>
DO= 1/2 BD=
1/2脳
6=3.
鍦?/p>
Rt
鈻?/p>
AOD
涓紝鐢卞嬀鑲″畾鐞嗭紝寰?/p>
AD=鈭?AO虏+DO虏)=鈭?4虏+3虏)=5.
鈭磋彵褰?/p>
ABCD
鐨勫懆闀夸负
4AD=4脳
5=20.
3.
璇佹槑锛氣埖鍥涜竟褰?/p>
ABCD
鏄彵褰紝鈭?/p>
AD=AB,AC卤
BD
锛?/p>
DO=BO,
鈭粹柍
ABD
鏄瓑鑵颁笁瑙掑舰锛屸埓
AO
鏄瓑
鑵?/p>
鈻?/p>
ABD
浣庤竟
BD
涓婄殑楂橈紝涓嚎锛屼篃鏄垹
DAB
鐨勫钩鍒嗙嚎锛屸埓
AC
骞冲垎鈭?/p>
BAD.
鍚岀悊鍙瘉
AC
骞冲垎鈭?/p>
BCD,BD
骞冲垎鈭?/p>
ABC
鍜屸垹
ADC.
4.
瑙ｏ細鏈?/p>
4
涓瓑鑵颁笁瑙掑舰鍜?/p>
4
涓洿瑙掍笁瑙掑舰
.
绗?/p>
7
椤电粌涔犵瓟妗?/p>
瑙ｏ紝鎵�鐢昏彵褰?/p>
AB-CD
濡傚浘
1-1-32
鎵�绀猴紝浣垮瑙掔嚎
AC=6cm
锛?/p>
BD=4cm.
1.2
1.
璇佹槑锛氬湪
鈻BCD
涓紝
AD//BC,
鈭粹垹
EAO=
鈭?/p>
FCO
锛堜袱鐩寸嚎骞宠锛屽唴閿欒鐩哥瓑锛?/p>
.