Area Synopsis

Formulas

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)2

4. The line joining the mid-point of a side of a triangle to the positive vertex is called the median.