Y by Adventure10
Four rods
are freely jointed at
and
and move in a plane so that the shape of the quadrilateral can be varied.
and
are the mid-points of
and
respectively. In one position of the rods, the angle
is acute. Show that this angle remains acute no matter how the shape of
is changed









This post has been edited 1 time. Last edited by parmenides51, Jul 13, 2019, 6:14 PM
Reason: source typo
Reason: source typo