D. I think im not sure with this one
The best choice would probably be the third option from the top. Since by using the distance formula you can solve for the length or distance of each of the sides of the triangle, and check to see if it is equal. As would be in an equilateral triangle.
Slope wouldn’t be best for the last leg or bottom leg as there is no change in y and x.
-1 because x is on the left and y is always on the right
