Diagonals of Polygons

What does it mean if diagonals are perpendicular (⊥)?

• They bisect the vertex

• Where they intersect is a 90˚ angle

• They are equal

Which of the following is FALSE about the polygon shown in the diagram?

• There are 4 sides

• There are 4 vertices

• There are 4 diagonals

• None of the above

How many diagonals are there in a quadrilateral?

• 1

• 2

• 3

• 4

What is a diagonal in a polygon?

• A line of a polygon

• A segment of a polygon

• A segment from one vertex to another vertex of a polygon

• A segment from one side to another side of a polygon

In the diagonal formula we dive by 2 because:

• We need to multiply the number of diagonals

• to avoid double counting diagonals

• to add more diagonals to the polygon

• to remember the formula

How many diagonals does a 9-gon have?

• 54

• 27

• 9

• 18

How many diagonals does a 80-gon have?

• 80

• 77

• 3080

• 2085

How many diagonals does a 400-gon have?

• 79400

• 400

• 200

• 79500

What is the formula to find the number of diagonals in a polygon?

In the diagonal formula, what does (n-3) represents?

• It represents the number of diagonals just from one vertex

• It represents the number of sides a polygons has

• It represent the number of sides minus 3

• It represent the number of vertices a polygon has