One way is to type it into your trusty TI and use the table from presing stat and then stat againg then calc then 4
so the equation that I got from your set of points is y=1.983333333333333x+0.80555555555
There are 180 degrees in total inside a triangle.
If something is equilateral that means that all the angles are equal.
180/3 equals 60 degrees.
That means that all angles of an equilateral triangle are always equal to each other and if you must know, are 60 degrees
Vertical angles i believe is the right answer to this problem