Because in equilateral triangle the , all sides should be equal
if come in the point of isosceles triangle the 2 sides should be equal always

All equilateral triangles are isosceles:
An equilateral triangle is a type of triangle in which all three sides are equal in length. Since the definition of an isosceles triangle is a triangle in which at least two sides are of equal length, it is clear that all equilateral triangles are isosceles triangles. In an equilateral triangle, all three sides are equal, so at least two sides are of equal length.

Not all isosceles triangles are equilateral:
An isosceles triangle is a type of triangle in which at least two sides are of equal length. However, not all isosceles triangles have all three sides equal in length, which is the defining characteristic of an equilateral triangle. In an isosceles triangle, only two sides are equal, while the third side can be of a different length. Therefore, not all isosceles triangles are equilateral triangles.

Justification:
To understand the justification for the statement, it is important to know the definitions of an equilateral triangle and an isosceles triangle.

- Equilateral Triangle: A triangle in which all three sides are equal in length.
- Isosceles Triangle: A triangle in which at least two sides are of equal length.

From the definitions, it is clear that all equilateral triangles are isosceles triangles because in an equilateral triangle, all three sides are equal. This means that at least two sides are of equal length, satisfying the definition of an isosceles triangle.

However, not all isosceles triangles are equilateral triangles because in an isosceles triangle, only two sides are equal in length. The third side can have a different length. Therefore, an isosceles triangle can have two sides of equal length, but the third side may not be equal in length to the other two sides.

In summary, all equilateral triangles are isosceles because they have at least two sides of equal length. On the other hand, not all isosceles triangles are equilateral because they may have two sides of equal length but the third side may have a different length.