In the applet below, there are three groups of 4 sided quadrilaterals, all of which have their interior angles sum to 360 degrees. Since Group 1, Group 2, and Group 3 all contain quadrilaterals, they must somehow be different in order for them to be in different groups.
You can move the quadrilaterals, and for some of them, also drag their points to change the length of their sides. You can drag the quadrilaterals, but you do not need to reorganize them into different groups.
Based on your observations, why do you think these quadrilaterals are categorized this way? Since they all have four sides and their interior angles sum to 360 degrees, what else could make them different? Write your observations and answers below.