Can any side of a triangle be labeled as its base? explain.

Sometimes, for it depends on the triangle. Take a right triangle, for instance. In a right triangle, the hypotenuse is always greater than the two legs. Therefore, you cannot label any side as the base, since the sides are different. In an equilateral triangle, on the other hand, all of the sides and angles are the same. Therefore, no matter which way you turn the triangle, every side is equal. In this sense it doesn't matter which side is labeled as the base. So, it really depends on the kind of triangle you're referring to.