The length of DE is 6 inches.
I can see that from the image, DE is a horizontal line segment that is 6 units long. This is because the x-axis is labeled in units, and DE spans 6 units on the x-axis.
we know that
The triangle XYZ and DEF are similar triangles
therefore
The ratio of their corresponding sides is equal
12/8 = 9/x
x = 8 * 9/12
x = 6 Units.
Therefore the length of DE is 6 inches.