Explicație pas cu pas:
1. a) AM/AB=AN/AC
2/8=5/20
40=40 ADEVARAT =>MN||BC
b) AN=10-8=2
AM/AB=AN/AC
3/15=2/10
30=30 ADEVARAT =>MN||BC
c) AB=14, AC=30
AM/AB=AN/AC
6/14=10/30
180=140 FALS=> MN nu e paralel cu BC
d) AN=30-24=6
AM/AB=AN/BC
4/24=6/ 30
144=140 FALS => MN nu e paralel cu BC
