How to cut /trim a photo at any angle?

In the above image. I loaded all 3 images into one file.

Then I made guides at the center of the document.

Then I used the shape tool to draw a triangle centered over the entire canvas - too big, so you can't see it.

Then I snapped guide lines to the boundry of the triangle. This gave me the points for the 120 deg. angles.

In the topmost layer I used the pen tool to draw a path, as you can see in the above screen shot. which I made a vector layer mask by having it selected the clicking on the mask icon in the layer's panel, while holding ctrl/cmd.

I then held alt/opt, and dragged that layer mask to the layer below to copy it.

I then edited the vector shape to create the next 120 deg mask, as you can see by the shape of the mask thumbnail.

By doing these two layer mask, I didn't need to create one for the last layer. The layer masks overlap themselves, so there should be no white edges.