Answer:
x= 9 inches
Explanation:
Hello
I can help you with this.
in this case, we have two similar triangles, let's see
Step 1
identify the rigth triangles.
1) the first triangle has these dimensions
hypotenuse( remember, the longest side)= unknown=H
adjacent side(the horizontal)=6 +x
opposite side(the vertical)=10
2) the second triangle has these dimensions
hypotenuse( remember, the longest side)= unknown=h
adjacent side(the horizontal)=6
opposite side(the vertical)=4.
As these triangles keep the same proportion and in both cases we know the length of the legs, we can establish a relationship
Step 2
establish a relationship
let's compare the opposite side and the adjacent side
triangle 1 (the bigger)

Triangle 2

were the proportions are equal, so

at this point, just isolate x to find its value
Step 3
isolate x

remember the units of measure ( Inches)
x= 9 inches
I really hope it helps, have a nice day.