Applied Mechanics and Graphic Statics
Lami's theorem states that

If three forces acting on a point can be represented in magnitude and direction by the sides of a triangle, the point will be in the state of equilibrium
Three forces acting at a point are always in equilibrium
Three coplanar forces acting at a point will be in equilibrium if each force is inversely proportional to the sine of the angle between the other two
Three coplanar forces acting at a point will be in equilibrium, if each force is proportional to the sine of the angle between the other two

ANSWER DOWNLOAD EXAMIANS APP

Applied Mechanics and Graphic Statics
The following is in unstable equilibrium

A satellite encircling the earth
A uniform solid cone resting on a generator on a smooth horizontal plane
A uniform solid cone resting on its base on a horizontal plane
A solid cube resting on one edge

ANSWER DOWNLOAD EXAMIANS APP