A diagonal
diagonal
diagonal
Perpendicular
It's a straight line for example within a square that joins opposite corners
A line is a straight path that extends infinitely or endlessly in opposite directions. A straight path that joins two points is called a line segment.
diameter
A bimedian is a line which joins the midpoints of opposite sides of a quadrilateral or tetrahedron.
Diameter Diameter radius
A straight line that joins one vertex to another vertex.
mid-segment
bisector?
There are 6 square faces, each with 4 corners. Since each corner joins two squares, there are 6 * 4 / 2 =12 vertices. A cuboctohedron has 12 vertices, 14 faces, and 24 edges.