把四面体看作一个平放在桌面上的三角形ABC(P是内部一点),
BC=a,CA=b,AB=c,PA=A,PB=B,PC=C
我们总可以让 11=a。
12有3种可能。
第1种可能: 12=b,可以有24种变化。
1: a,b,c,A,B,C=11,12,13,14,15,16,
2: a,b,c,A,B,C=11,12,13,14,16,15,
3: a,b,c,A,B,C=11,12,13,15,14,16,
4: a,b,c,A,B,C=11,12,13,15,16,14,
5: a,b,c,A,B,C=11,12,13,16,14,15,
6: a,b,c,A,B,C=11,12,13,16,15,14,
1: a,b,c,A,B,C=11,12,14,13,15,16,
2: a,b,c,A,B,C=11,12,14,13,16,15,
3: a,b,c,A,B,C=11,12,14,15,13,16,
4: a,b,c,A,B,C=11,12,14,15,16,13,
5: a,b,c,A,B,C=11,12,14,16,13,15,
6: a,b,c,A,B,C=11,12,14,16,15,13,
1: a,b,c,A,B,C=11,12,15,13,14,16,
2: a,b,c,A,B,C=11,12,15,13,16,14,
3: a,b,c,A,B,C=11,12,15,14,13,16,
4: a,b,c,A,B,C=11,12,15,14,16,13,
5: a,b,c,A,B,C=11,12,15,16,13,14,
6: a,b,c,A,B,C=11,12,15,16,14,13,
1: a,b,c,A,B,C=11,12,16,13,14,15,
2: a,b,c,A,B,C=11,12,16,13,15,14,
3: a,b,c,A,B,C=11,12,16,14,13,15,
4: a,b,c,A,B,C=11,12,16,14,15,13,
5: a,b,c,A,B,C=11,12,16,15,13,14,
6: a,b,c,A,B,C=11,12,16,15,14,13,
第2种可能: 12=c,可以有24种变化。
1: a,b,c,A,B,C=11,13,12,14,15,16,
2: a,b,c,A,B,C=11,13,12,14,16,15,
3: a,b,c,A,B,C=11,13,12,15,14,16,
4: a,b,c,A,B,C=11,13,12,15,16,14,
5: a,b,c,A,B,C=11,13,12,16,14,15,
6: a,b,c,A,B,C=11,13,12,16,15,14,
1: a,b,c,A,B,C=11,14,12,13,15,16,
2: a,b,c,A,B,C=11,14,12,13,16,15,
3: a,b,c,A,B,C=11,14,12,15,13,16,
4: a,b,c,A,B,C=11,14,12,15,16,13,
5: a,b,c,A,B,C=11,14,12,16,13,15,
6: a,b,c,A,B,C=11,14,12,16,15,13,
1: a,b,c,A,B,C=11,15,12,13,14,16,
2: a,b,c,A,B,C=11,15,12,13,16,14,
3: a,b,c,A,B,C=11,15,12,14,13,16,
4: a,b,c,A,B,C=11,15,12,14,16,13,
5: a,b,c,A,B,C=11,15,12,16,13,14,
6: a,b,c,A,B,C=11,15,12,16,14,13,
1: a,b,c,A,B,C=11,16,12,13,14,15,
2: a,b,c,A,B,C=11,16,12,13,15,14,
3: a,b,c,A,B,C=11,16,12,14,13,15,
4: a,b,c,A,B,C=11,16,12,14,15,13,
5: a,b,c,A,B,C=11,16,12,15,13,14,
6: a,b,c,A,B,C=11,16,12,15,14,13,
第3种可能: 12=A,可以有24种变化,其中有12种=另外12种。
1: a,b,c,A,B,C=11,13,14,12,15,16,
2: a,b,c,A,B,C=11,13,14,12,16,15,
3: a,b,c,A,B,C=11,13,15,12,14,16,
4: a,b,c,A,B,C=11,13,15,12,16,14,
5: a,b,c,A,B,C=11,13,16,12,14,15,
6: a,b,c,A,B,C=11,13,16,12,15,14,
1: a,b,c,A,B,C=11,14,13,12,15,16,
2: a,b,c,A,B,C=11,14,13,12,16,15,
3: a,b,c,A,B,C=11,14,15,12,13,16,
4: a,b,c,A,B,C=11,14,15,12,16,13,
5: a,b,c,A,B,C=11,14,16,12,13,15,
6: a,b,c,A,B,C=11,14,16,12,15,13,
合计能够搭建24+24+24/2=60个不同的四面体。 |