The meaning of Erastus is Lovely and  Beloved. Its origin is Variant of the Greek name Erastos. Erastus is a form of Erastos and is generally pronounced like eh RAS tus. This name is mostly being used as a boys name. Last year it ranked 4,160th in the U.S. Social Security Administration list of most popular baby boy names.
Which undefined term is needed to define an angle? Plane Point Ray Line. Undefined, you need a line to define an angle (if you're looking for undefined terms). This is because, if you think about it, a ray is part of a line.
protractor - An instrument used to measure the degrees of an angle. ray - A ray begins at a point and goes off forever in one direction. right angle - An angle that measures 90Â° In a right triangle, one angle measures 90Â°. skew - Lines that are neither parallel nor perpendicular.