A.
three forces acting at a point will be in equilibrium5
B.
three forces acting at a point can be represented by a triangle, each side being proportional to forcef
C.
if three forces acting upon a patticle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
D.
if three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two