Question

Un dreptunghi are latura egala cu 21cm patrati iar l=3cm.Atunci L=?

Answer 1

A = L • l
21 = 3 • L
L = 21/3
L = 7 cm

Answer 2

$\text{Formula ariei dreptunghiului} : \boxed{A=L \times l} \\ 21 \ cm^2 = L \times 3\ cm \\ L = \frac{21\ cm^2}{3\ cm} \\ L= 7\ cm$