Question

consider the diagram. lines a and d are non - coplanar. parallel. perpendicular. skew.

Explanation:

Step1: Define non - coplanar

Non - coplanar means not lying on the same plane. But we need to check other definitions.

Step2: Define parallel

Parallel lines are in the same plane and never intersect. But from the diagram, lines \(a\) and \(d\) are not in the same plane.

Step3: Define perpendicular

Perpendicular lines intersect at a right - angle (\(90^{\circ}\)). But lines \(a\) and \(d\) do not intersect.

Step4: Define skew

Skew lines are non - parallel, non - intersecting, and non - coplanar. From the diagram, lines \(a\) and \(d\) fit this definition.

Answer:

skew.