For immune function, the following doses have been taken by mouth: 40 IU of vitamin D3 daily for 20 years to 100,000 IU of vitamin D3 bimonthly for 12 months, or 10,000 IU daily. For inflammatory bowel disease, 0.5 micrograms of alfacalcidol has been taken by mouth daily.
Intersecting lines. Two or more lines that meet at a point are called intersecting lines. That point would be on each of these lines. In Figure 1, lines l and m intersect at Q. Figure 1 Intersecting lines. Perpendicular lines. Two lines that intersect and form right angles are called perpendicular lines.
More Geometry Lessons. Parallel and Skew Lines. Parallel lines are two lines in the same plane that never intersect. In a coordinate plane, parallel lines can be identified as having equivalent slopes. Parallel lines are traditionally marked in diagrams using a corresponding number of chevrons (or arrows).