Question

Un dreptunghi are perimetrul de 24 cm si lungimea cu 2 cm mai mare ca latimea. aflati aria dreptunghiului.

Answer 1

P=(L+l)*2=24cm
L=l+2cm
A=?

L+l=24cm:2
L+l=12cm
L=l+2cm
l+2cm+l=12cm
2l+2cm=12cm
2l=12cm-2cm
2l=10cm
l=10cm:2
l=5(cm latimea)
L=5cm+2cm
L=7(cm lungimea)
A=L*l
A=7cm*5cm
A=35cm²(aria)

Answer 2

Pd=2l+2L
mai stim ca L=l+2
inlocuim 2l+l+2+l+2=24
4l+4=24
4l=24-4
4l=20
l=20:4
l=5 cm
L=5+2
L=7 cm
Ad=l*L=5*7=35 cm