I'd start by copying a chunk of the photo with the triangular sign on it, then with Grids to help me, distort it back to a fairly even shape. Then put the text on it:
Then fiddle with the text colour so it's more plausible. Black ain't right, of course. Here, I used darkish grey, on Multiply mode:
Then group those two layers, move them back into place, lower the opacity of the group, and distort it again so it fits neatly over the real triangle:
Then turn off the spare triangle layer (or delete it entirely). Then rasterize the type layer, make it a smart object layer instead, and apply a little blur so it's plausible: