Hitori's rock garden is in the shape of a trapezoid. The garden has an area of 60m squared and a depth of 8m.

The front width is double the back width. With out changing the front or back widths by how much must hitori increase the depth of his garden to double it area. I already know the answer I just need to know how to how it in a equation

Let w = smaller width
Let h = height (depth)
larger side = 2w

Area = 3w / 2 * h
Area = 3/2 w * h

If w doesn't change, to double A, h must be doubled.

2A = 2 * 3/2 w * h = 3/2 w * 2h <=====

The depth must be doubled

Let fronth width be x.

60 m² = 4(x + 2x)

3x = 15 --> x = 5 m

120 m² = d(15)

Answer: d - 4 = 4 m