It follows that the total number of triangles will be equal to the number of three-line combinations that can be chosen from a group of six lines. How do you calculate that? Choose a line, any line.

Revise trigonometric ratios of sine, cosine and tangent and calculate angles in right-angled triangles with this Bitesize GCSE Maths Edexcel guide.

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 ...