Get to know the names of all the main 2-d shapes, how to recognise them and what their properties are. There’s a downloadable worksheet at the end of this post for you to try, and see how well you know 2-d shapes.

Triangles

Equilateral triangle

o       All sides equal in length and all angles the same (all 60o)

Isosceles triangle

o       Two sides equal in length and two angles equal

Right-angled triangle

o       One angle is 90o

Scalene triangle

o       Sides are all different lengths, angles are all different sizes

 

Quadrilaterals

Square

o       Four sides of equal length

o       Four angles equal, all 90o

o       Opposite sides are parallel

Rectangle

o       Four angles equal, all 90o

o       Opposite sides are equal length

o       Opposite sides are parallel

Rhombus

o       Four sides of equal length

o       Opposite angles are equal

o       Opposite sides are parallel

Parallelogram

o       Two pairs of parallel sides

o       Opposite sides are equal length

o       Opposite sides are parallel

o       Opposite angles are equal

Kite

o       Two pairs of equal sides

o       Equal sides are adjacent to each other

o       Two equal angles

Arrowhead

o       Two pairs of equal sides

o       Equal sides are adjacent to each other

o       Two equal angles

 

Trapezium

o       One pair of parallel sides

Isosceles trapezium

o       One pair of parallel sides

o       Non-parallel sides are equal in length

 

Polygons

Regular polygons have all sides equal in length and all angles equal

Names of polygons you should get to know:

Polygon               Number of sides

Pentagon             5

Hexagon              6

Heptagon             7

Octagon               8

Nonagon              9

Decagon              10

Dodecagon         12

 

Naming 2-D shapes worksheet