What triangle with at least two congruent sides?
A. Equilateral triangle
B. Isosceles triangle
C. Scalene triangle
D. None of the above
The correct answer and explanation is:
The correct answer is B. Isosceles triangle.
An isosceles triangle is defined as a triangle with at least two congruent sides. In other words, two sides of the triangle are of equal length. The angles opposite these sides are also equal. This characteristic makes the isosceles triangle distinct from other types of triangles.
Let’s break it down further:
- Equilateral triangle: This is a specific type of isosceles triangle where all three sides are congruent. While it satisfies the condition of having at least two congruent sides, it goes a step further by having all three sides equal. However, the key to the question is that it asks for a triangle with “at least two congruent sides,” so the equilateral triangle technically fits, but it is not the most specific answer here.
- Scalene triangle: This type of triangle has no congruent sides. All three sides are of different lengths. This makes it the opposite of what the question asks for, as it does not meet the condition of having at least two congruent sides.
- Isosceles triangle: This triangle has exactly two congruent sides, fulfilling the question’s requirement. The angles opposite the congruent sides are also equal. This triangle can have varying angle measurements, but the defining characteristic remains the two congruent sides.
Thus, the correct answer is the isosceles triangle because it is defined by having at least two congruent sides, whereas the other choices either do not meet the requirement or are more specific.