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Fie A, B, C puncte coliniate astfel incat |AB|=[tex] \frac{3}{4} [/tex]·|AC|. Daca |AB|=9 cm, iar M si N sunt mijloacele segmentelor [AB] si [BC], calculati |MN|
Va rooog, dau coronita!!


Răspuns :

A          M           B       N       C
I_______I_______I_____I_____I

AB=AM+MB
AM≡MB
AM=AB/2=9/2
AM=4,5cm
MB=4,5cm
AM=3AC/4
9=3AC/4
3AC=9X4
AC=36/3
AC=12cm
AC=AB+BC
BC=AC-AB
BC=12-9
BC=3
BN≡NC
BC=BN+NC
BN=BC/2=3/2
BN=1,5cm
NC=1,5cm
MN=MB+BN
MN=4,5+1,5
MN=6cm