Formulas for the perimeter of figures

The perimeter of a geometric figure is the length of the boundary of the geometric figure.


Perimeter of a triangle

perimeter of a triangle

The perimeter of a triangle is the sum of the lengths of its sides.

P =a + b + c ,

where P is the perimeter of the triangle,
a, b, c are the lengths of the sides of the triangle.

Perimeter of a square

perimeter of a square

Perimeter of a square by side length

perimeter of a square by side length

The perimeter of a square equals the length of its side multiplied by four.

P = 4 · a ,

where P is the perimeter of the square,
a is the length of the side of the square.

Perimeter of a square by diagonal length

perimeter of a square by diagonal length

The perimeter of a square equals the length of its diagonal multiplied by two square roots of two.

P = 2 · 2 · d ,

where P is the perimeter of the square,
d is the length of the diagonal of the square.

Perimeter of a rectangle

perimeter of a rectangle

The perimeter of a rectangle equals twice the sum of the sides adjacent to one angle.

P = 2 · a + b ,

where P is the perimeter of the rectangle,
a, b are the lengths of the sides of the rectangle.

Perimeter of a parallelogram

perimeter of a parallelogram

The perimeter of a parallelogram equals twice the sum of the sides adjacent to one angle.

P = 2 · a + b ,

where P is the perimeter of the parallelogram,
a, b are the lengths of the sides of the parallelogram.

Perimeter of a rhombus

perimeter of a rhombus

The perimeter of a rhombus equals the length of its side multiplied by four.

P = 4 · a ,

where P is the perimeter of the rhombus,
a is the length of the sides of the rhombus.

Perimeter of a trapezoid

perimeter of a trapezoid

The perimeter of a trapezoid is the sum of the lengths of its sides.

P = a + b + c + d ,

where P is the perimeter of the trapezoid,
a, b are the lengths of the bases of the trapezoid,
c, d are the lengths of the lateral sides of the trapezoid.

Circumference

circumference

Circumference via radius

circumference via radius

The circumference equals twice the product of the radius and pi.

P = 2 · π · r ,

where P is the circumference,
r is the radius of the circle.

Circumference via diameter

circumference via diameter

The circumference equals the product of the diameter of the circle and pi.

P = π · d ,

where P is the circumference,
d is the diameter of the circle.

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