Triangle ABC: Identifying Side DC and Its Properties

To solve this problem, we start by examining the notation typically associated with a triangle and its sides. In standard geometric practice, the sides of a triangle are denoted by referring to the two vertices that form the endpoints of each side. For triangle ABC, the sides could normally be expressed as AB, BC, or CA.

The question proposes that "DC" is a side of triangle ABC. To analyze this, we consider the vertices of triangle ABC: A, B, and C. For "DC" to be considered a side, D must be an additional point that is explicitly mentioned or defined in the context of triangle ABC. However, the problem simply provides triangle "ABC" with no indication of point D being relevant in the triangle's primary structure of three vertices and three sides.

Given the lack of provision or clarification on point D's involvement in triangle ABC, side "DC" cannot logically be deduced as one of its sides because the naming convention explicitly bounds the potential sides to those vertices within the triangle, namely A, B, and C.

Therefore, based on our analysis and understanding of geometric conventions, the statement “DC is the side of triangle ABC” is not true.

Therefore, the correct answer to the problem is Not true.