* The perimeter of any closed figure is the total length of its boundary.
* Perimeter of the rectangle, P = 2 × (l + b) units.
* Perimeter of the square, P = (4 × S) units.
* Perimeter of the triangle, P = (a + b + c) units.
* Perimeter of the shape with equal sides = Number of sides × Length of a side.
* The area is the measure of the region/surface occupied by a closed figure.
* Area of a rectangle, A = length × breadth = (l × b) sq. units.
* Area of a square, A = side × side = (s × s) sq. units.
* Area of the right angled triangle, A = 1/2 (b × h) sq. units.
* The perimeter of a combined shape is the sum of the length of all outer sides of the shapes.
* The area of a combined shape is the sum of all the areas of regular/simpler shapes by which the combined shape is formed.