Let's draw the vertices of the triangle on a coordinate plane.
Shown below:
As you can see from the graph, The distance from A to B is equal to the distance from B to C.
The distance from A to C is larger than that of the distance between A to B (or B to C).
Thus,
2 sides are same
Equilateral Triangle is a triangle with 3 sides equal.
Isosceles Triangle is a triangle with 2 sides equal.
From the figure, we can clearly see that the triangle ABC is isosceles.