Hi! What distinguishes triangles from quadrilaterals other than their number of sides ?
Explanation from Alloprof
This Explanation was submitted by a member of the Alloprof team.
the answer to this question can be very elaborate.
There are numerous similarities: they are polygons (closed chain), they have sides (segments of lines), angles, vertices (corners), etc. There are a lot of differences as well, besides the number of sides which is not the same:
-A quadrilateral has 4 vertices. A triangle, 3.
-A quadrilateral has 4 interior angles. A triangle, 3.
-A quadrilateral has 4 exterior angles. A triangle, 3.
-The sum of the measures of the interior angles of a quadrilateral is 360 °. That of a triangle is 180 °.
-A quadrilateral has 2 diagonals. A triangle, 0.
-A quadrilateral can be crossed. A triangle, no.
-A quadrilateral can be convex or non-convex (concave). A triangle is always convex.
-There are quadrilaterals that are equilateral but not equiangular (diamonds, and some quadrilaterals that are equiangular but not equilateral (rectangles). Equilateral triangles are always equiangular and vice versa.