Measurement of the extent of a two-dimensional surface or shape in a plane is called area.
Area of the right angled triangle = ½ × base × height
Where a, b, c are the sides of the triangle, and s = semi-perimeter = (a + b + c) / 2
Brahmagupta - an Indian mathematician who worked in the 7th century, proved a generalised form of Heron’s Formula, to find the area of a quadrilateral.
Brahmagupta’s Formula for Area of Quadrilateral
The area A of a cyclic quadrilateral with sides a, b, c and d is given by:
Where s is the semi-perimeter of the quadrilateral:
s = (a + b + c + d) / 2
An equilateral triangle is a triangle with all three sides of equal length. An equilateral triangle has also three equal angles of 60°.
An isosceles triangle is a triangle with at least two sides of equal length. An isosceles triangle has also two angles of equal measure.
A parallelogram is a quadrilateral that has two pairs of parallel sides.
In a right-angled triangle, the square of the length of the longest side is equal to the sum of the squares of the other two sides containing the right angle.
A scalene triangle is a triangle with all three sides of unequal length.