[tex]\displaystyle\\
\text{Notam cu }O_1\text{ si } O_2 \text{ mijloacele diagonalelor trapezului.}\\\\
Lm=\frac{B+b}{2}=5~cm\\\\
O_1O_2=\frac{B-b}{2}=2~cm\\\\
\text{Scriem ecuatiile:}\\\\
\begin{cases}
\dfrac{B+b}{2}=5\\\\
\dfrac{B-b}{2}=2
\end{cases}\\\\
\begin{cases}
B+b=5\times2\\
B-b=2\times2
\end{cases}\\
\begin{cases}
B+b=10\\
B-b=4
\end{cases}~~~\text{Adunam ecuatiile}\\\\
2B=14\\\\
B=\frac{14}{2} \\\\
\boxed{\bf B=7~cm}\\
B+b=10\\
b=10-B=10-7\\
\boxed{\bf b=3}[/tex]
