9.44 ୋ 9
Շࡈ̬ᗙҖٙהϞ࿁Ꮠԉഃ (AAAA) אהϞ࿁ᏐᗙϓˢԷࣛ�̴
ࡁ݊щɓ֛Ч�ᜫҢࡁீཀሙੀݺਗ 9.2 ɓઞӺ�
ਞڝྡ�кᓙ ABCDE + FGHIJ ݊щ͍ᆽ�
E
D
C
A
B
2 cm
4 cm
40° 70°
H
G
I
F
J
3 cm
5 cm
18
即時訓練即時訓練
➥ ୦ᕚ 9D 17
ਞڝྡ�кᓙ ABCD + EFGH ݊щ͍ᆽ�
ί EFGH ʕ�
+EGH = +FEG �ʫ፹ԉ�FE # GH�
a +EHG = +FEG
` +EHG = +EGH
` EH = EG �ഃԉ࿁ᗙഃ�
= 4 cm
EF
AB = cm
cm
3
2 = 3
2
EH
AD = cm
cm
4
3 = 4
3
` EF
AB ! EH
AD
` ABCD + EFGH ʔ͍ᆽ�
A D
B C
3 cm
2 cm
E H
F G
3 cm
4 cm
ܓ二
例例 18
解
ABCD ձ EFGH ʔՈ௪�࿁Ꮠ
ᗙϓˢԷ�ٙሯ�
◀
࣬ኽהഗٙ༟ࣘ�̙щႭ
(a) ձ (b) ٙ࿁ྡҖ
ɓ֛݊ЧྡҖճ�
c
a
e
-- = -- = -- = --b
f
c
g
d
h
a e
g
d
(a)
(b)
b h f