Which of the following two-dimensional shapes can be rotated to create a cone?

Right triangle
Square
Circle
Ellipse

1 answer

To create a cone through rotation, a shape must have a line of symmetry that allows it to generate a circular base and converge to a point (the apex).

Among the options given:

  1. Right triangle: Yes, when a right triangle is rotated around one of its legs, it generates a cone.

  2. Square: No, rotating a square does not create a cone but rather a cylinder.

  3. Circle: Yes, when a circle is rotated around an axis, it can create a cone if it is truncated, but on its own, a circle alone doesn’t form a cone.

  4. Ellipse: Yes, rotating an ellipse around one of its axes can also create a conical surface, although it forms an elliptical cone.

In summary, the right triangle and the ellipse definitely can be rotated to create a cone, while the circle can under specific conditions. The square cannot.