i have 3 points on a plane, whose positions are fixed. and
one arbitrary point, it's position can vary.
i have to form a quadrilateral by making use of these 4
points , it may form concave or convex quadrilateral.
from this data one point is clear that 2 sides and 1
diagonal length are fixed. and i want to calculate the
length of another diagonal.
how do i do it??