ΌഃʿЧ�ɚ�9.43
ਞڝྡ�ʊ̬ٝᗙҖ ABCD ٙʫԉձ݊ 360c�༆ᙑ
މО ABCD ձ EFGH ӚϞ̙ঐ݊ЧྡҖ�
50°
60° 110°
A
D
C
B
130°
G
F
H
E
ί ABCD ʕ�
+BAD + +ABC + +BCD + +ADC = 360c
+BAD + 60c + 110c + 50c = 360c
+BAD = 140c
a +FEH = 130c
` +FEH ၾ ABCD ԉேʔഃ�
` ABCD ձ EFGH ӚϞ̙ঐ݊ЧྡҖ�
ܓ一
例例 17
解
ABCD ձ EFGH ʔՈ௪�࿁Ꮠ
ԉഃ�ٙሯ�
◀
ਞڝྡ�ʊ̬ٝᗙҖ ABCD ٙʫԉձ݊360c�༆ᙑމО̬ᗙ
Җ ABCD ձ EFGH ӚϞ̙ঐ݊ЧྡҖ�
A B C D
110°
70°
100°
75°
E F GH
17
即時訓練即時訓練
➥ ୦ᕚ 9D 7
(b) ˸ɨɓ࿁ྡҖʔՈ௪�࿁ᏐᗙϓˢԷ�ٙሯ�̴ࡁԨʔЧ�
1
1
2
2
3
2
1 1
W
Z
X
Y
HE
F G
EF
WX = FG
XY = EH
WZ = 1
2�Ш GH
YZ = 1
3�