In order to immediately get a ready-made unrolled lateral surface of a cone, click on the link.
To get an unfolded lateral surface of a truncated right circular cone, click on this link.
If you need a right circular cylinder or an oblique cylinder developments, let's click here.
An unrolled lateral surface of a truncated cylinder (a vent pipe elbow), is on this page.

If you are interested in the question of how to make an unfolded lateral surface of a cone on your own, without using online - calculators or programs, then this article is for you.

A cone is a simple geometric shape. At the base of cone is a circle, and a vertex of cone is a point.

To build the unfolded lateral surface of the cone, we need only two quantities - its height (H) and the diameter of the base (D).
According to them, from the formulas, we determine the length of the generatrix (A) of the cone and the circumference (L) of the base of the cone. These values will be needed later. [Fig.1]

The square of the hypotenuse (A) of a right-angled triangle equals the sum of the squares of the other two sides (H, D/2) - fig.1
free drawings

lateral surface of cylinder - circumference length (Fig. 1)

Next, mentally unwrap the cone (more precisely, the lateral surface of the cone). So, as shown in Fig.2, 3 and 4.

As a result, we get a sector of a circle, as seen in Figure 5.

To construct the resulting circular sector (which is the unrolled lateral surface of the cone), you will need two quantities:

  • The length of the generatrix (A) of the cone, which is already determined (previous article - How to make cone out of sheet)
  • Sector angle (U) - fig.5

We also determined the length of the sector arc (Ls), which is equal to the circumference (L) of the cone's base. The circle of the base, which was unfolded [Fig.5].

free drawings of unfolded lateral surfaces - the angle of the circular sector.

The sector angle is determined, the length of the generatrix of the cone is calculated earlier, now let's build an unfolded lateral surface of the cone.

You can read more about the cone in the Wikipedia article. And in this Owlcation article.

how to make cone out of paper
Axial cone height (h)
mm
Cone base diameter (D)
mm
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