Amap of a new dog park shows that it is triangular and that the sides measure 18.5m, 36.9m, and 16.9m. are the dimensions correct?

In order to check whether the length of the sides are applicable to form a triangle is that we have to make sure that the sum of the length of two side should be greater than the third side.

18.5 m, 36.9 m, and 16.9 m
18.5 m < 36.9 m +16.9 m
36.9 m < 18.5 m +16.9 m
16.9 m < 18.5 m + 36.9 m

So the dimensions are correct!