Which type of triangle has at least two congruent sides and angles?

The isosceles triangle is characterized by having at least two sides that are congruent, meaning they are of equal length. This property leads to the angles opposite those sides being congruent as well. Therefore, in any isosceles triangle, if two sides are the same, the angles adjacent to those sides will also be the same.

In contrast, an equilateral triangle is a specific type of isosceles triangle where all three sides and angles are congruent, but it is not the only type of triangle that meets the criteria outlined in the question. Thus, while all equilateral triangles are isosceles, not all isosceles triangles are equilateral.

A scalene triangle, on the other hand, has no sides of equal length, which means all three sides and all three angles are different.

A right triangle is defined by having one angle that measures exactly 90 degrees, but it does not specifically require any congruent sides or angles.

Understanding these distinctions clarifies why the isosceles triangle is the correct answer, as it meets the criterion of having at least two congruent sides and angles.