Abstract: A measure to use to draw a line perpendicular to a reference line. The measure comprises a top surface with opposite first and second ends and opposite first and second edges that extend between the first and second ends. The top surface has a first set of indicia that represent a first scale and a second set of indicia that represent a second scale. The first and second scales are distance scales and have a common zero point. The second scale is a multiple of the first scale. The first and second scales are used to construct the two sides and the hypotenuse of a right triangle with one of the two sides being on the reference line so that a line perpendicular to the reference line can be constructed with little or no calculations required by the user.