To show that the area of a triangle is half the product of the base and the height.
Triangle: A triangle is one of the basic shapes in geometry: a polygon with three corners or vertices and three sides or edges which are line segments.
Right angled triangle:
A right angled triangle has one of its interior angles measuring 90°. The side opposite to the right angle is the hypotenuse; it is the longest side of the triangle. For a right angled triangle with sides a, b, c where c is the hypotenuse, a2 + b2 = c2.
Acute angled triangle:
A triangle that has all interior angles measuring less than 90° is an acute triangle or acute-angled triangle. For an acute-angled triangle with sides a, b, c where c is the greatest side, a2 + b2 > c2.
Obtuse angled triangle:
A triangle that has one interior angle that measures more than 90° is an obtuse triangle or obtuse-angled triangle. For an obtuse-angled triangle with sides a, b, c where c is the greatest side, a2 + b2 < c2.