Réponses

2014-03-13T18:20:57+01:00
Exercice 60 :
Le triangle CDE est-il rectangle en E ?
AÊD + ADE = 90°
ADE + EDC = 90°
Donc : AED = EDC
DEC = 180° - (56° + 34°) = 90°
Le triangle CDE est donc rectangle en E

Exercice 68
A = 3 + 5
      2 + 4
A = 8/6
A = 2 x 4 / 2 x 3
A = 4/3

B = 3/2 + 5/4
B = 3 x 2 / 2 x 2 + 5/4
B = 6/4 + 5/4
B = 10/4
B = 2 x 5 / 2 x 2
B = 5/2

C =  3      +    5
     2 + 4      2 + 4
C = 3/6 + 5/6
C = 8/6
C = 2 x 4 / 2 x 3
C = 4/3

D = 3 + 5 + 3 + 5
        2          4
D = 8/2 + 8/4
D = 8 x 2 / 2 x 2 + 8/4
D = 16/4 + 8/4
D = 24/4
D = 4 x 6 / 4 x 1
D = 6/1
D = 6