The deck in Hopes backyard is round.It has 5 post evenly spaced around the edge to support a trellis. For her birthday party , she wants to connect each post to all the other post with crepe paper streamers. How many streamers will she need?
If you draw the 5 posts (dots) on a piece of paper and connect the dots, you will need 10 lines to connect them all to each other, so she will need 10 streamers.