In geometry, an object exhibits symmetry if it looks the same after a transformation, such as reflection or rotation. Symmetry is important in art, math, biology and chemistry.

The same number of marks indicate equal lengths. are used to represent segments of equal length on diagrams. Arcs close arcs (annotation) Curved marks inside the vertex of a shape.

Learn about properties of triangles with this BBC Bitesize Maths article. For students between the ages of 11 and 14.