Question

Un dreptunghi de lungime L si latime l are perimetrul egal cu 120 dm.Calculati L si l stiing ca...... A) L=2l B)L=3l

Answer 1

a)
P=120 dm=2(L+l)
L=2l
2(2l+l)=120
2×3l=120
6l=120
l=120:6
l=20 dm
L=2×20
L=40 dm

b)
P=120 dm=2(L+l)
L=3l
2(3l+l)=120
2×4l=120
8l=120
l=120:8
l=15 dm
L=3×15
L=45 dm

Answer 2

A) L=2l
2•L+2•l= 120 dm
4l+2l=120 dm
6l= 120 dm
l= 20dm
L=40 dm

B) L=3l
2•L+2•l= 120 dm
6l+2l=120 dm
8l=120 dm
l=15 dm
L=45 dm