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;
When the rectangle is enlarged by 6 the initial length and breadth are both increase to a multiple of 6;
So, the final area will be;
Substituting A =lb from the first initial area, we have;
Therefore, the area of the enlarged photo is 36 times the original.