1) longueur l =90-(15*2)=60m
Aire =l*L= 60*15=900 m**2
2) l = 90-(40*2)=10m
Aire =l*L = 10*40=400m**2
3) l=90-2x
4)a) A(30)=30*(90-2*30)=900
b)A(0)=0*(90-2*0)=0
A(5)=5*(90-2*5)=400
A(10)=10*(90-2*10)=700
A(15)=15*(90-2*15)=900
A(20)=20*(90-2*20)=1000
A(25)=25*(90-2*25)=1000
A(30)=30*(90-2*30)=900
A(35)=35*(90-2*35)=700
A(40)=40*(90-2*40)=400
A(45)=45*(90-2*45)=0
