Actually it really is called an edge!
A ruler has markings, a straight edge does not. In "straight edge and compass" constructions, you are not allowed to mark the straight edge. Things that are impossible using only a straight edge and compass are possible if markings are allowed (for example, it's possible to trisect an angle using a marked straight edge).
An edge is an area of a 3D figure where two faces meet to form a line segment.
A perpendicular edge is a side of a plane shape that is at right angles (90 degrees) to another edge.
The line round the edge of the circle.
Actually it really is called an edge!
A Ruler
The length of the edge of a circle.
A ruler has markings, a straight edge does not. In "straight edge and compass" constructions, you are not allowed to mark the straight edge. Things that are impossible using only a straight edge and compass are possible if markings are allowed (for example, it's possible to trisect an angle using a marked straight edge).
An edge is an area of a 3D figure where two faces meet to form a line segment.
A perpendicular edge is a side of a plane shape that is at right angles (90 degrees) to another edge.
The line round the edge of the circle.
A segment is part of a circle created by drawing a line from a point on the edge to another point on the edge.
Generally a ruler is a straight edge, but it can be anything... I generally just use a spare pencil.
ask ur math teacher ;)
A straight edge is basically another name for a ruler, or it could be anything that makes straight lines.
An edge is a straight line as part of a polygon. It can also be the straight line joining two faces of a solid which has polygonal faces.