Angle: Two intersecting line form an angle between the two lines.

Complementary Angles:. Two angles are said to be complementary to each other if the sum of the two angles adds up to be 90 degrees.

Extrapolate: Estimating the location of an unknown point based upon 2 or more known values and the assumed math equation defining those points. On this site the math equation will always be a line and we will simply be extending the line to another point. The best example I know of is shooting a rifle; the line is the defined by the two sights, and the extension point is the target..

Fixture: In reference to tools: A fixture is a tool that allows that facilitates easy duplication of a measurement or process. For example, a rip-fence is a fixture on a saw is used to hold the saw or material at a fixed distance through-out the cut making the cut consistent for the whole length of the cut.

Interpolate: Estimating the location between two known points. In most cases on this site that will be a line between the two known points. However, it could be any kind of path between the two points, but in most cases on this site we will be working with lines.

Level: A surface is said to be level if it is smooth and a ball placed upon it will remain perfectly still, or if water spilled on the surface is as likely to flow in one direction as it is in any other direction.

Level: A tool used to determine if a surface is level.

Plumb: The condition where a vertical surface or pole is perpendicular to a level surface.

“Right Angle” . An angle between two lines of exactly 90 degrees. This means the two lines are perpendicular to each other. Also called “being square” by craftsmen.

Square: Geometric shape definition: A four sided geometric shape where all four sides are the same length and all the angles between adjacent sides are 90 degrees. (A specific type of rectangle).

Square: Math definition: Squaring a number means multiplying it by itself. This comes from calculating the area of the geometric shape of a square.

Square: Craftsman use: Two walls of a structure are said to be square with each other if there is exactly a 90 degree angle (perpendicular) between those two. A square is a tool used to make a mark at 90 degrees to another edge surface of a piece of material.