Sagot :
a) 2* [(3x+4)+2x]
b) 2* [(3*499.2+4)+2*499.2]
= 2* [(1497.6+4)+998.4]
= 2* [(1501.6)+998.4]
= 2* (1501.6+998.4)
= 2* 2500
= 5000
a) périmètre du cerf - volant
2(3x+4+2x)=2(5x+4)=10x+8
b)si x=499,2
10x+8=4992+8=5000 cm
c)10x+8=218
10x=218-8=210
x=210/10
x=21 cm