Area and perimeter are important measurements used to describe polygons, which are closed two-dimensional shapes with straight sides.

The formulas for calculating the area and perimeter of various polygons depend on the specific type of polygon.

Let’s explore the formulas for some common polygons:

Rectangle:

Area: A = length × width

Perimeter: P = 2 × (length + width)

Square:

Area: A = side × side (or A = side^2)

Perimeter: P = 4 × side

Triangle: There are different formulas for the area of a triangle based on the information given:

If the base (b) and height (h) are known: Area: A = (1/2) × base × height

If the lengths of all three sides (a, b, c) are known (Heron’s formula): Semi-perimeter: s = (a + b + c) / 2 Area: A = √(s × (s – a) × (s – b) × (s – c))

If the triangle is a right-angled triangle, with one angle measuring 90 degrees: Area: A = (1/2) × base × height (where base and height are the two sides that form the right angle)

Regular Polygon: For a regular polygon with n sides and side length s:

Area: A = (1/4) × n × s^2 × cot(π/n)

Perimeter: P = n × s

Circle:

Area: A = π × radius^2

Perimeter (Circumference): C = 2 × π × radius

Parallelogram:

Area: A = base × height

Perimeter: P = 2 × (side1 + side2)

Trapezoid:

Area: A = (1/2) × (sum of parallel sides) × height

Perimeter: P = sum of all sides

Step by Step video instructions on making model of area and perimeter