PERIMETER AND AREA - ESSENTIAL POINTS
- Perimeter is the distance around a closed figure whereas area is the part of plane occupied by the closed figure.
- Area is the measure of the part of plane or region enclosed by it.
- Basic formulas for areas and perimeters.
- Perimeter of a square = 4 × side
- Perimeter of a rectangle = 2 × (length + breadth)
- Area of a square = side × side
- Area of a rectangle = length × breadth
- Area of a parallelogram = base × height
- Area of a triangle = 1/2 (area of the parallelogram generated from it) = ½ × base x height
- Area of equilateral triangle = × side
- Area of a circle = πr2, where r is the radius of the circle.
- The distance around a circular region is known as its circumference.
- The ratio of circumference and diameter of a circle is a constant is denoted by π (pi).
- Circumference of a circle = πd, where d is the diameter of a circle and π = 22/7 = 3.14 (approximately).
- Based on the conversion of units for lengths, studied earlier, the units of areas can also be converted:
- 1 cm2 = 100 mm2
- 1 m2 = 10000 cm2
- 1 hectare = 10000 m2
