## Arithmatical - Area

DIRECTIONS : Important Facts and Formulae
1. Area of a rectangle = (Length × Breadth).
2. Perimeter of a rectangle = 2(Length + Breadth).
3. Area of a square = (side)2 = 1 / 2 (diagonal)2
4. Area of 4 walls of a room = 2 (Length + Breadth) × Height.
5. Area of a triangle = 1 / 2 × Base × Height.I). Area of a triangle = √s(s-a)(s-b)(s-c) where a, b, c are the sides of the triangle and s = 1/ 2 (a + b + c)II). Area of parallelogram = (Base x Height).Area of a rhombus = 1 / 2 (Product of diagonals).III). Area of a trapezium =1 / 2 (sum of parallel sides) x distance between them.Iv). Area of a circle = ΠR2, where R is the radius.
6. Circumference of a circle = 2ΠR.I). Circumference of a semi-circle = ΠR.II). Area of semi-circle = ΠR2 / 2.
 FUNDAMENTAL CONCEPTS
1. Results on Triangles : 1. Sum of the angles of a triangle is 180°.2. The sum of any two sides of a triangle is greater than the third side.3. Pythagoras Theorem :In a right-angled triangle, (Hypotenuse)2=(Base)2 + (Height)24. The line joining the mid-point of a side of a triangle to the positive vertex is called the median.