Although the triangles are shown to be right triangles, there’s nothing saying that they are. If it’s an equilateral triangle, then there’s nothing wrong with this diagram.
The four people are drawn as the corners of a square whose sides are 6ft long. (If it were a rhombus, the shortest distance between two of the pairs of people would be less than 6 ft.)
By definition, the angle between adjacent sides of a square is 90 degrees. These are right triangles.
It’s reasonable to assume that although the two diagonals have an incorrect value that the creators intent was to portray them as equal which supports this being a square.
Although the triangles are shown to be right triangles, there’s nothing saying that they are. If it’s an equilateral triangle, then there’s nothing wrong with this diagram.
The four people are drawn as the corners of a square whose sides are 6ft long. (If it were a rhombus, the shortest distance between two of the pairs of people would be less than 6 ft.)
By definition, the angle between adjacent sides of a square is 90 degrees. These are right triangles.
Of course it’s supposed to be a square, but if this were a proof, you couldn’t assume they’re right angles
That's a fair comment.
But it is also not possible for all four sides of the square (or rhombus) and both diagonals to be 6 ft in length.
If it's a square, if the sides are 6ft, then the diagonals are longer. Or if the diagonals are 6 ft, then the sides are shorter.
If it's a rhombus, it would be possible for the sides to be 6ft and one diagonal to be 6ft, but the other diagonal would be much longer than 6ft.
Tl,dr: the figure as drawn is geometrically impossible.
It’s reasonable to assume that although the two diagonals have an incorrect value that the creators intent was to portray them as equal which supports this being a square.