API Reference > geometry-core > ArraysAndInterfaces > IndexedXYCollection > crossProductXAndYIndexIndex crossProductXAndYIndexIndex MethodAbstract Return the cross product of vectors from origin to points at indexA and indexB crossProductXAndYIndexIndex(origin: Readonly<WritableXAndY>, indexA: number, indexB: number): undefined | number Parameter Type Description origin Readonly<WritableXAndY> origin for vector indexA number index of first target within the array indexB number index of second target within the array Returns - undefined | number undefined if either index is out of bounds Defined in geometry3d/IndexedXYCollection.ts Line 64 Last Updated: 11 June, 2024