Answer:
x = 16 2/3
Explanation:
The altitude divides the triangle into similar triangles. We can form the ratio between the hypotenuse and the short leg for two of the triangles. Those ratios will be a proportion:
10/6 = ((x-6) +6)/10
100/6 = x . . . . . multiply by 10 and simplify
x = 16 2/3