Projection of Line AB To draw the projection line AB we can start by drawing horizontal and vertical planes intersecting at point B. Then project onto these based on its inclination angles. Horizontal Plane: Project end A B plane. The distance between projectors is given as 60 mm. Vertical True Length Apparent Angles determine true length apparent length angles use following formulas: Length (TL) AB: TL = ?(AB^2 + BC^2) where plane BC height (AL) AL Distance mm Angles: Angle with 40° 30° We formulas angles to calculate AB.