1 4 1 A B
10 20 2 ( ) ( 10 80 18 20 180 19 15 150 2 2 15cm 150 20 1 10 150
15 80 100 180 200 280 303 W20 250 100 100 50 100 500 3 20 3 150 1800 2 3600 4 4
y f h hy 2 /4f h75 2 /(41800)0.781( 5 1 60 2 (3) 5 6 AA' 1/3 6 1 2 l/3 6
7 h fy 2 /4h y 8 7 8 1/3 200#280 303(w20) 5 10 280
9 9 ) 10 10 303 303½W14 304 W10 ( 111) 2030 11
( ) 12 5 1a 1b 1c 2 1de 13 12 13
14 14 6 15 1 153 152 15
16 17 16 17 1 17a b 2 3 16 A 161 B 162
C 163 D 164 10 18 18 45
d = L D a F a L a 15 1820 5 L 15 a 25 d 1515 2.5 / 180 2.5 3.5 1.41 d 5 6 6 ABC A B B C A B 280 19 20 19 20 201 20 2 3 0.0003 2 3 0.5 0.00015 3 204
AB BC CA A + B = 1 B + C = 1 C + A = 2 A2B 1c0 A B C 0.5 21 21 405 1.8 45360 10 15 20 2517 12.5 22 1 221
2 222 23 34 3 23 223 1/2 1.31.5 10 31.7 23.2 20 15 150 20 160 23 120 23
24 24 25 10 4 25 26 208 5 40 104 S8 26 1.9 110 1
27 A B 28 27 28 29 29A 29B 23 29
A 45 B 45 C 30 30AB) 30A 45 30B 30C PDF pcfans 1989 pcfans pcfans 2003.08.10 MSN: eituoz@hotmail.com