The area of a rectangle is the product of the length and the breadth of the rectangle.
lets assume the initial length and breadth of the rectangle are l and b, the initial area will then be;
[tex]\begin{gathered} A=l\times b \\ A=lb \end{gathered}[/tex]When the rectangle is enlarged by 6 the initial length and breadth are both increase to a multiple of 6;
[tex]\begin{gathered} l\rightarrow6l \\ b\rightarrow6b \end{gathered}[/tex]So, the final area will be;
[tex]\begin{gathered} A_f=6l\times6b \\ A_f=36lb \end{gathered}[/tex]Substituting A =lb from the first initial area, we have;
[tex]\begin{gathered} A_f=36lb=36A \\ A_f=36A \end{gathered}[/tex]Therefore, the area of the enlarged photo is 36 times the original.