[image]

 any 3d soild object

• a line and a point
• 2 intersecting lines
• 2 parallel lines
• 3 noncollinear points

2 planes that intersect

• if the line is perpendicular to 2 lines on a plane then it is perpendicular to the plane
• if a line is perpendicular to a plane, then it is perpendicular to every line on the plane that passes through the foot