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°).
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 means "right angle" |
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 and  show equal sides |
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Each internal angle is 90° |
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Opposite sides are parallel and of equal length (so it is a Parallelogram). |
Play with a rectangle:
Area of a Rectangle
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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.
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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
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A rectangle has two diagonals, they are equal in length and intersect in the middle. |
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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?
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Diagonal Length = √(52 + 122) = √(25 + 144) = √169 = 13 cm |