At first we should know that:
The sum of two sides of the triangle must be greater than the third side
So, we will chick the given side lengths 34 km, 27 km, 58 km
So,
34 + 27 = 61 > 58
34 + 58 = 92 > 27
27 + 58 = 85 > 34
So, the side lengths could form a triangle.
