Answer:
15
Explanation:
TU is parallel to IJ. So ∠I and ∠T are corresponding angles, and ∠U and ∠J are corresponding angles.
By AA similarity, ΔHTU and ΔHIJ are similar.
Write a proportion:
HT / HI = HU / HJ
Plug in values:
4 / 10 = x / (x + 9)
Cross multiply:
4 (x + 9) = 10x
4x + 36 = 10x
36 = 6x
x = 6
So HU = 6, and HJ = 6 + 9 = 15.