Rectangle -Geometry Formulas


A rectangle is a 2-dimensional shape/polygon with four sides, four vertices, and four right angles. The two opposite sides in the rectangle are equal and parallel to each other.

Area of Rectangle:

The area of a rectangle is the space covered by the shape. Alternatively, the space within the perimeter of the rectangle is the area of a rectangle.

Area = l × b


A rectangle is 5 m wide and 3 m high, what is its Area?


Area = 5 m × 3 m

= 15 m2

Perimeter of a Rectangle:

The Perimeter is the distance around the edges.

Perimeter = 2(l+b)


A rectangle is 12 cm long and 5 cm tall, what is its Perimeter?


Perimeter = 2 × (12 cm + 5 cm)

= 2 × 17 cm

= 34 cm

Diagonals of a Rectangle:

Diagonal “d” = √(a2 + b2)


A rectangle is 12 cm wide, and 5 cm tall, what is the length of a diagonal?


D = √(122 + 52)

= √(144 + 25)

= √169

= 13 cm

Properties Of Rectangle:

  • A rectangle is a quadrilateral with four equal internal angles.
  • Each internal angle of a rectangle measures 90°.
  • As the opposite angles of a rectangle are equal, a rectangle is also a parallelogram.
  • The opposite sides of a rectangle are equal and parallel.

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