Yes, the triangles are similar, and the criteria used is AA.
How to know if the triangles are similar?
Two figures are similar if one is a dilation of the other. This would mean that the two figures have the same shape, but different size.
Here we can see two equilateral triangles, and we can see that the interior angle that is unique in both cases is 20°.
Because the triangles are equilateral, the other two angles must be equal in both triangles:
20 + 2*x = 180
2*x = 180 - 20
x = 160/2
x = 80°
In the two triangles we will have two angles of 80° and one of 20°, and both are equilateral, so yes, the triangles are similar, and the criteria used is AA.