To classify each triangle based on their given side lengths or angles, let’s analyze them carefully:

Triangle A

• Side lengths: 6, 6, and 10
• Since two sides are equal, Triangle A is an Isosceles triangle.
• It is not equilateral (all sides would need to be equal) or scalene (no sides equal).

✔ Isosceles

Triangle B

• Side lengths: 5, 7, and 11
• All three sides are different, so Triangle B is a Scalene triangle.
• It is not isosceles or equilateral.

✔ Scalene

Triangle C

• Angles: 40°, 40°, and 100°
• Two angles are equal (40°), which means two sides are also equal, making Triangle C an Isosceles triangle.
• It is not equilateral (angles would all need to be 60°) or scalene.

✔ Isosceles

Triangle D

• Angles: 60°, 60°, and 60°
• All angles are equal (60°), which means all sides are also equal. Triangle D is an Equilateral triangle.
• An equilateral triangle is also isosceles because at least two sides are equal, but its classification remains equilateral.

✔ Equilateral

Final Summary of Classifications:

Let me know if you need further explanations for any triangle! Here are some related questions to explore:

1. How do you determine a triangle’s type based on side lengths?
2. How are angles in a triangle related to its sides?
3. Can a triangle be both isosceles and scalene? Why or why not?
4. How can you classify triangles based solely on their angles?
5. What is the sum of the internal angles of any triangle?

Tip: Remember, an equilateral triangle is always isosceles, but not every isosceles triangle is equilateral!