What don't you get about the problem ?
Answer: Where is the image or PDF?
Answer:

Step-by-step explanation:
This problem can be solved using the pythagorian theoreme:

Where:



We isolate our incognita an we get:

We supplant with the given data:





Simplify
2/4z + 1 = 2/4z + 1
Answer: D. Infinite solutions
The triangles are similar by the SSS (side-side-side) similarity theorem because the sides of the two triangles are in proportion (5/15 = 3/9 = 4/12)
Hope this helps =)