Assignment: Create from the 6 matches of the 4-re triangle, each side of which will be equal to the 1st match.
Do you want to look at the solution of the puzzle?
Answer, step one: Out of the first three matches, lay out the triangle.
Step Two: Take the remaining three matches for the heads ...
... and put them so that they touch the tips to the corners of the first triangle.
You got four identical triangles !!!