What is common in the given figure (1) and (2)?
Is figure (1) that of the triangle? If not, why?

Hint: Here we are given two figures and we need to find the common thing between them. We can see that both the figures are made out of the three line segments and therefore this is the common thing and triangles must be a closed figure and therefore we can see which one is a triangle or not.

Complete step-by-step answer:
Here we are given two figures and we need to find the common thing in both of them.

For the common thing we need to see the figures carefully and analyse them. Now we can see that both the figures have the common thing that both the figures are made up of the line segments even if the shapes are different. Both are made up of $3$ line segments. This is the common thing that both of the figures possess.
Now we are also asked whether the figure (1) is a triangle or not. We must know that triangles are made up of three line segments. Here both are made up of three line segments but in the triangle we must know that triangle is a closed figure.
We can see that figure (1) is not a closed figure whereas figure (2) is closed. Hence we can say that figure (1) is not a triangle as it is not a closed figure.

Note: The student must know that triangle can also be of various types. There are three angles and sides in the triangle. So the triangle with two sides equal is an isosceles triangle while with all sides equal is an equilateral triangle and with all the three sides different is the scalene triangle.