The latus rectum is the focal chord perpendicular to the axis. For $y^2$=4ax, it is the segment from (a, 2a) to (a, -2a) with length 4a. The semi-latus rectum is 2a. The endpoints correspond to t=1 and t=-1 (since t1*t2=-1). The latus rectum is the shortest focal chord. The area of the triangle formed by the tangents at the endpoints of the latus rectum and the latus rectum itself is 2$a^2$.