Get the coordinates of the vertices of the pyramid

I want to get the coordinates of the vertices of the base of the pyramid
tempsnip

const geometry2 = new THREE.ConeGeometry(10, 20, 4);

      const material2 = new THREE.MeshBasicMaterial({ color: 0xffff00 });

      const cone = new THREE.Mesh(geometry2, material2);

      scene.add(cone);

      for (let index = 0; index < cone.geometry.attributes.position.count; index++) {

         const point0Coordinate = new THREE.Vector3().fromBufferAttribute(cone.geometry.attributes.position, index);

         point0Coordinate.applyMatrix4(cone.matrixWorld);

      }

i tried to use fromBufferAttribute
but got wrong values
full code here

Hi!
Which values are wrong?

HI, how y can see in fiddle, red vertex has coordinate (10, -5, 0) but point fromBufferAttribute outputs
10, -5, 6.123233998228043e-16

Is a very tiny value, close to zero.

i thought it was close to 6) thank you