Question

Explain why having three congruent angles in two triangles is not a good way to prove two

triangles are congruent. Come up with a counter example, you can describe or draw it.

Answer 1

Draw an equilateral triangle with side lengths of 1. Each angle here is 60 degrees, which is true of any equilateral triangle.

Now draw another equilateral triangle that has side lengths of 2 units. Clearly this triangle is not the same size as the previous one, but the angles are all still 60 degrees.

We have an example in which there are 2 triangles with the same angles, but the triangles are not congruent. Therefore, having info about congruent angles only isn't sufficient to prove triangles to be congruent.