Let's first consider all the different types of triangles:
- Scalene Triangle: all side lengths of this triangle are of different lengths
- Isosceles Triangle: the lengths of two of the three sides of the triangle are equal
- Equilateral Triangle: lengths of all the sides are equal
What we are looking for:
⇒a triangle with all the sides of different length
The only triangle to fit that requirement is: Scalene Triangle
Hope that helps!