Learn about angles in triangles and quadrilaterals 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 trick now is to consider the isosceles triangle ABC shown below, whose angles are 36°, 72° and 72°. Bisecting the top angle yields a triangle BCD, which is similar to ABC.

Properties of symmetry: - Students may notice symmetry in the isosceles and equilateral triangles and non-symmetry in the scalene triangles Informal recognition of these properties may be helpful in ...