9.28 ୋ 9
31. ίྡʕ�ABC ݊ɓૢٜᇞ�AB = DB ձ AD = CD = CB�
ண +DAC = x�
(a) ༊˸ x ڌͪ+DBC�
(b) Ӌ+DAC�
32. ίྡʕ�BDC ձ AEB ேٜ݊ᇞ�AB = AC�DA = DE�
+CAD = 20c ձ +EDB = 10c�Ӌ +DAE�
33. ίྡʕ�ABCD ݊ɓࡈ͍˙Җ�Ͼ 3ADE ݊ɓࡈഃᗙɧԉҖ�
Ӌ i�
34. ίྡʕ�ABCD ݊ɓૢٜᇞ�AB = BC = CD = BE = CE�Ӌ
+AED�
ܓ三
35. ίྡʕ�AEB�AFC ձ BDC ேٜ݊ᇞ�+EDF = 50c�
(a) ༊˸ x ڌͪ +ABC�
(b) ༊˸ y ڌͪ +ACB�
(c) Ӌ +BAC�
36. ྡʕᜑͪ3ABC ձ 3PQR�ADEB ݊ɓૢٜᇞ�
AC = AE�BC = BD�+DCE = x ձ+QPR = 2x�
+ACB ձ +QPR ঐщଡ଼ϓɓࡈ̻ԉ�༊༆ᙑЫٙ
ഈࣩ�
D
A C
B
x
A
B C
D
E
10°
20°
B
C
A
D
E
i
➥ Է 12
E
B C
D
A
D
A
E F
B C
x y
50°
A
D
E
x
C
B
P
R
Q
2x
解釋題