Say you have a small triangle drawn on the hypotenuse of a larger right angle triangle. Would it be possible to find the missing dimensions on the large triangle? Knowing the dimensions of the small triangle, can you find the length of the missing side and the hypotenuse on the large triangle or is more information needed?
The image is not to scale, just for demonstration purposes.
If the top and bottom sides are parallel, then this information is enough, as the right triangles are similar. Otherwise, more information is needed.