Answer:
These two triangles are similar triangles, so they have congruent angle measures.
If you take a look at the smaller triangle, two of the angles are 45 and 81. This means that the third angle would be 54.
If the third angle measures 54 degrees, that would mean angle 1 is also 54 degrees, since these triangles are similar, and similar triangles have congruent angle measures.
Let me know if this helps!