There is a separate branch in the subject of mathematics which deals with the various kinds of shapes and figures. This branch is called Geometry. Geometry deals with 2d shapes, 3d shapes, lines, ...

Polygons can be regular or irregular in shape. A polygon is a closed 2D shape with at least three sides. A regular polygon is a polygon with all equal sides and angles. An irregular polygon is a ...

A scalene triangle has 3 sides of different lengths and 3 unequal angles. An isosceles triangle has 2 sides of equal length. (The dashes on the lines show which are equal in length.) The angles at the ...