The width of the garden increased by 8 meters, so the area of the garden increased by 456 square meters.

The length of the garden is 456÷8=57 (meters).

∫ Garden area = Garden length × Garden width

∴ Garden area = 57× (15+8) = 57× 23 =1311(square meter)

If not, you can ask me again. I hope it can be adopted. O(∩_∩)O Thank you!