What is Diagonal?
- It (diagonal) is a line segment.
- Polygons are plane figures having at least three sides and angles and usually, it is used to identify figures having five or more sides and angles.
- Vertex is a corner of the shape.
So, diagonal is a line segment connecting two non-adjacent vertices of a polygon. It joins the vertices of a polygon excluding the edges of the figure. The following shapes have a diagonal drawn on them:
Some more examples:
Here, in the figure of the stop sign, three diagonals are connected by non-consecutive vertices. In the figure the kite, one diagonal is connected by two opposite vertices.
Number of diagonals in a polygon with n vertices =
So, from this formula; we can easily calculate the number of diagonals in a polygon.
The given table shows the number of diagonals in different polygons:
|Shape Names||Number of Vertices||Number of Diagonals|
Length of a diagonal
Diagonal of a square = a√2
Therefore, for the above picture, d = a√2
Diagonal of a rectangle = √l2+b2
|Fun Facts about Diagonal|
– The word diagonal comes from Middle French diagonal, Latin diagōnālis, and from Ancient Greek diagṓnios where diá means ‘across’ and gōnía means ‘angle’.