Now, the fundamental rule of proper triangles is that all angles inside the triangle will ALWAYS add to 180. Another thing that we notice, is that each angle corresponds with the opposite side (Angle A goes with line BC). Know, if each angle corresponds with each side, and we see that all sides of the triangle are equal, that means that all angles are equal as well. Knowing this, the simple solution would be to divide 180 by 3. So, when we do this, we would then know that our answer is 60 degrees (if you have any questions/concerns, please ask me.)