Question

Dimensiunile unui dreptunghic sunt iinvers prop. cu 0,5 si 1,2 iar aria lui este 15 cm ²
Aflati perimetrul dreptunghiului.

Answer 1

0,5=5/10=1/2
1,2=12/10=6/5
L=lungime
l=latime
A=arie
a=l×L
15=l×L
invers proportionale
L/1/2=l/6/5⇔L:1/2⇔L×1/2=L/2
l/6/5=l:6/5=l×5/6=5l/6
L/2=5l/6
6L=2×5l
6L=10l⇒L=10l/6
15=L×l
15=10l/6×l
15=10l²/6
15×6=10l²
90=10l²
90/10=l²
9=l²⇒l=√9⇒l=3
L=10l/6⇔L=10×3/6⇔l=30/6⇔l=5