Bonjour,
Voir figure ci-jointe.
1) 1 carré = 1cm, donc A carré = 1*1=1cm2
2) A figure = aire rectangle - aire triangle vert - aire triangle rouge
A figure = 4*3-[(3*1)/2]-[(3*3)/2]
= 12-3/2-9/2
= 24/2-3/2-9/2
=12/2
Aire figure = 6cm2
3) Aire triangle = (b*h)/2
= (4*3)/2
= 12/2
Aire triangle = 6cm2
Bonne journée
