Lesson

Let's review the properties of shapes to help us in this lesson.

How many vertices does each shape have?

a

Worked Solution

b

Worked Solution

Idea summary

Vertices are the corners where two edges meet.

This video shows us how to find diagonals in two dimensional polygons.

Consider the following shape.

a

What is the name of the shape?

A

Square

B

Trapezium

C

Pentagon

Worked Solution

b

How many diagonals does a pentagon have?

Worked Solution

Idea summary

A diagonal is a straight line (line segment) that runs between opposite vertices. The vertices can't be adjacent to each other, and we don't count diagonals in the opposite direction separately.