FYI: I do not fully know this answer, but I think what I put in the answer is correct.
Answer:
Explanation:
If you look at the lengths of the triangle, two of them are the same, so it is an isocoles triangle. And you know one of them is 61 degrees, so in that case, the other side is also 61 degrees.
A triangle has 180 degrees in total, and now that you know two sides of it, you know that
180-61*2= x
=180-122=x
=58=x
Hope this helps, maybe not though