Answer: 11
Step-by-step explanation
There are 4 small blue triangles in row 1.
Then 2 more in row 2. And finally 2 more blue small triangles in row 3.
That's 4+2+2 = 8 blue triangles congruent to the small black one.
Then there are 3 more white small triangles
This will get the grand total to 8+3 = 11
We ignore the larger white triangle since it's not congruent to any of the small ones. We also ignore any combination/gluing of smaller triangles to form larger triangles.
---------------
Another way to find the answer:
When connecting midsegments of an equilateral triangle, the largest triangle sub-divides into 4 congruent equilateral triangles. The split is 1 to 4. Meaning 1 thing becomes 4. The count has quadrupled.
Do this quadrupling for 3 of the medium sized triangles (the corner ones shown in the diagram) and that sub-divides things to the next level. You should get 4 small triangles per those 3 medium sized triangles mentioned. That's 4*3 = 12 small triangles in total. 1 of which is black, while the other 12-1 = 11 are either white or blue.