1、2
2、110°
3、45°
4、4 cm
5、5
6、4π
7 - 10 C B C D
11、∵ ∠AOB = 2∠BOC,
∴ AB = 2BC,
∴ ∠AOB = 2∠BAC.
12、∵ PC平分∠APB,
∴ AC = BC,AC = BC,
∵ ∠ACB = 60°,
∴ △ABC为等边三角形.
13、连接BC,CF,△OBC ≌ △OFC(SAS),
∴ BC = CF,BC = CF.
14、连接OD,OE,△ABC ∽ △AOD,OD = 43.
15、(1)PC = 23;
(2)不发生变化,∠CMP = 45°
16、2π3 - 3.
17、(1)y = 33x + 4;
(2)32π3 + 43.
18、(1)OE = OF,
∵ Rt△AFO ≌ Rt△CEO;
(2)连接BD,△AFO ∽ △ABD,
∴ AF/AB = AO/AD,AF·AD = 2r²
19、(1)连接AE,DE = DA,AE ⊥ BC,∠C = ∠CED(等角的余角相等),
∴ CD = DE = DA;
(2)△ABC ∽ △EAC,ACEC = BCAC,
∴ AC² = BC·EC;
(3)若AE = EB,则∠B = 45°,∠C = 45°,cosC = 22.
20、(1)作直径AE,连接BE,△ABE ∽ △ADC,
∴ AB/AD = AE/AC,(1)∵ AE = 2R,
∴ AB·AC = 2R·AD,
(2)略
21、AB = 1,BF = 2,AF = 3,sin∠AFB = 12,∠EBF = 60°,S阴影 = 2π3-32
22、(1)连接PC,∠ACP = ∠ACB = ∠BAD,∠ABE = ∠ACP,
∴ ∠ABE = ∠BAD,
∴ AE = BE;
(2)略;
(3)P为AC的中点
23、(1)连接OD,∠OAD = ∠ADO,∠ODC = 90°,
∴ ∠CED = ∠AEO = ∠CDE,
∴ CE = CD;
(2)上述仍然成立
24、(1)3圈;
(2)设OA = 1,点O经过的路程 = OA·2π×3 = 6π