Rectangle

(Jump to Area of a Rectangle or Perimeter of a Rectangle)

A rectangle is a four-sided flat shape where every angle is a right angle (90°).

Rectangle    
quadrilateral right key means "right angle"
quadrilateral equal key and quadrilateral equal key2show equal sides
 
right arrow Each internal angle is 90°
right arrow

Opposite sides are parallel and of equal length (so it is a Parallelogram).

Play with a rectangle:

Area of a Rectangle

rectangle  

The Area is the width times the height:

Area = w × h

Example: A rectangle is 6 m wide and 3 m high, what is its Area?

Area = 6 m × 3 m = 18 m2

Perimeter of a Rectangle

The Perimeter is the distance around the edges.

rectangle perimeter  

The Perimeter is 2 times the (width + height):

Perimeter = 2(w+h)

Example: A rectangle has a width of 12 cm, and a height of 5 cm, what is its Perimeter?

Perimeter = 2 × (12 cm + 5 cm) = 2 × 17 cm = 34 cm

Diagonals of a Rectangle

rectangle diagonals  

A rectangle has two diagonals, they are equal in length and intersect in the middle.

rectangle diagonal calculation  

The Diagonal is the square root of (width squared + height squared):

Diagonal "d" = √(w2 + h2)

Example: A rectangle has a width of 12 cm, and a height of 5 cm, what is the length of a diagonal?

rectangle diagonal example Diagonal Length = √(52 + 122) = √(25 + 144) = √169 = 13 cm