bonjour,
exo 2 :
il n'y a pas d'unités(cm, m...)
1) AN/AC=AM/AB=NM/CB
x/35 = 6/28
x = (6*35)/28 = 7,5
x =7,5
2) AM/AB=AN/AC=NM/BC
3/x = 2/39
x = (39*3)/2 = 58,5
x = 58,5
3) IR/IK=IS/IJ=RS/KJ
13/39 = x/(x+10)
39*x = 13(x+10)
39x = 13x+130
39x-13x = 130
x = 5
exo 3 :
(VP)//(KJ)
IV/IJ = IP/IK=KJ/VP
2,5/3 =2/IK
2,5*IK = 3*2
2,5*IK = 6
IK = 6/2,5 = 2,4
2) AN/AI = AM/AP = MN/IP
2/1,5 = 1,5/IP
IP = (1,5*1,5)/2 = 1,125
IP = 1,125