Cone template
A cone net with a sector that rolls into the sloping side and a circle with teeth for the base. It is made for geometry lessons, party hats and craft projects.
- Set it up your way
- Print or PDF, Letter or A4
- Free, no sign-up
On this page
A cone is the odd one out among the solids because its side is curved, yet it comes from a flat shape. Cut a slice of a circle, like a piece of pie, and roll the straight edges together: you get the sloping side.
What prints
The sheet is called "Cone Template". The upper part is a sector with its point (the apex) at the top and a curved edge at the bottom. A grey glue tab runs along one straight edge. Underneath is a base circle ringed with small grey teeth.
The proportions are fixed: the base circle's radius is 0.42 of the sector's radius. That means the curved edge of the sector is exactly as long as the circle's circumference, so the pieces fit. At medium size the sector angle is about 151 degrees. The key at the bottom shows the cut line, the dashed fold and the glue tab.
The settings
- Shape: Cone.
- Size: Three choices, Small, Medium and Large, scaled to 0.75, 1.0 and 1.2 times the middle one. If a size runs past the page, the whole net is scaled down.
How to fold it
Cut around the sector and its tab, then cut out the toothed circle. Roll the sector until the tab slides under the other straight edge, and glue it. Hold the cone with the open end up. Fold the teeth of the circle upward, put glue on them and press the base inside the wide opening. If you do not want a base, skip the circle.
Card of 65 to 110 lb weight keeps the cone upright. Print at 100%. Use blunt-tip scissors with children, and ask an adult to cut the small teeth if they are hard to control.
Worked example: a cone hat for a class party
Mr. Kim's first graders are making party hats for a class celebration. He prints the Large cone on bright card stock, omits the base, and attaches a ribbon through two holes he punches near the glue tab. Before gluing, each child decorates the sector with stickers and with shapes cut from the shapes to cut out sheet.
The older helpers test the rule on their own. They measure the arc, then measure the circle and compare. The two are close, so the cone closes without a gap. A few children roll the sector too loosely and get a flat, wide hat. He shows them how tightening the roll makes a taller, narrower one, which opens a short talk about what changes when the opening gets smaller.
Related pages
The cylinder template shares the toothed-circle idea, and the surface area and volume worksheets give numbers to try on the finished model.