Answer:
a) Scalene
b) Scalene
c) Isosceles
Explanation:
Here, we want to get the type of triangle with the given side lengths
a) 2,5,4
All the side lengths are different, the triangle type is scalene triangle
b) 9,12,13
All side lengths are different, the triangle type is scalene triangle
c) 4,4,9
Two side lengths are equal
The triangle type is an isosceles triangle