A rectangle is a four-sided flat shape where every angle is a right angle (90°).
the little squares in each corner mean "right angle"
|Each internal angle is 90°|
Play with a rectangle:
Area = a × b
Example: A rectangle is 6 m wide and 3 m high, what is its Area?
The Perimeter is the distance around the edges.
The Perimeter is 2 times (a + b):
Perimeter = 2(a+b)
Example: A rectangle is 12 cm long and 5 cm tall, what is its Perimeter?
Diagonals of a Rectangle
A rectangle has two diagonals, they are equal in length and intersect in the middle.
A diagonal's length is the square root of (a squared + b squared):
Diagonal "d" = √(a2 + b2)
Example: A rectangle is 12 cm wide, and 5 cm tall, what is the length of a diagonal?
There is also a special rectangle called the Golden Rectangle: