Here's a demo
% Order is important!
% Line 1 is defined by the first two values. Line 2 is defined by second two values.
x = [5, 6, 5, 6]; % x coordinates of 4 points
y = [4.5, 6.5, 6.5, 4.5]; % y coordinates of 4 points
% Define function that calculates intersection point
getIntersect = @(x,y)[x(1)*y(2)-x(2)*y(1), x(3)*y(4)-x(4)*y(3)] / [y(2)-y(1), y(4)-y(3); -(x(2)-x(1)),-(x(4)-x(3))];
% xyIntersect is a [1 x 2] vector if (x,y) coordinates of intersection.
xyIntersect = getIntersect(x,y);
