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

Discusses the properties and types of triangles, explaining that a triangle is a closed figure with three sides and angles. It categorizes triangles into equilateral, isosceles, scalene, obtuse ...

The three doweled pieces of this unpainted wooden model can be arranged either as a rectangle or as an obtuse-angled triangle. Compare models 1985.0112.190 through 1985.0112.202.

The Springfield Preservation Trust lists properties annually seen as in most peril of being lost through deterioration and calamity including many properties that have been featured multiple years.