Formulas For Area and Perimeter of Shapes

Area of Circle = πr² unit² = π x (length of radius)² Note: π can be approximated by 3.14 or the fraction 22/7

Area of Circle

Area of Triangle = ½ bh unit² = ½ (base) x (height) unit²

Area of Triangle

Area of Parallelogram = bh = (base) x (height) unit²

Area of a Parallelogram

Area of Rectangle = bh unit² = (base) x (height) unit²

Area of a Rectangle

Area of Square = s² unit² = (side length) x (side length) unit²

Area of a Square

Area of a Trapezoid = ½h(b₁ + b₂) unit² = ½ (height) x (top base length + bottom base length)

Area of a Trapezoid

Circumference of a Circle = πd = 2πr = (π) (diameter) = 2 (π) (radius) Note: π can be approximated by 3.14 or the fraction 22/7

Circumference (Perimeter) of a Circle

Perimeter of Parallelogram = 2b + 2l = 2(length of base) + 2(slant height of sides)

Perimeter of Parallelogram

Perimeter of Rectangle = 2L + 2W = 2(side length) + 2(side width)

Perimeter of Rectangle

Perimeter of Square = 4s = 4 (length of one side)

Perimeter of Square

Perimeter of Trapezoid = a + b + c + d = (length base 1) + (length side 1) +(length base 2) + (length side 2)

Perimeter of Trapezoid

Perimeter of Triangle = a + b + c = (length side 1) + (length side 2) + (length side 3)

Perimeter of Triangle

Perimeter of a Regular Polygon = n (side length) where n is the number of sides

Perimeter of a Regular Polygon