Let's review the properties of shapes to help us in this lesson.
How many vertices does each shape have?
Vertices are the corners where two edges meet.
This video shows us how to find diagonals in two dimensional polygons.
Consider the following shape.
What is the name of the shape?
How many diagonals does a pentagon have?
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.
manipulates, classifies and draws two-dimensional shapes, including equilateral, isosceles and scalene triangles, and describes their properties