7th Grade Math > Properties of Shapes > Principles for Calculating the Number of Diagonals in a Polygon, Practice Worksheets
Diagonals A diagonal is a line segment connecting two non-adjacent vertices in a polygon. Understanding the concept of diagonals is crucial because the number of diagonals in a polygon is related to the number of its vertices. To calculate the number of diagonals, we first need to determine the number of diagonals that can be drawn from a single vertex. Once we know this, we can use the same rule for each vertex in the polygon. Let's examine this by looking at polygons with different numbers of vertices, such as quadrilaterals, pentagons, and hexagons. In a quadrilateral, there is 1 diagonal from each vertex. In a pentagon, there are 2 diagonals from each vertex. In a hexagon, there are 3 diagonals from each vertex. As the number of vertices increases by one, the number of diagonals from each vertex also increases by one. So, how many diagonals can be drawn from a vertex in an n-sided polygon? Looking at the pattern: In a quadrilateral (4 sides), there is 1 diagonal from each verte...