A!! -2 and 2 are the x values of the coordinates which are 4 units apart, being 4 units in LENGTH 1 and -2 are 3 units apart and them being in the y part of the coordinate it’s 3 units wide
So the length is 4*28=112mm The width would be calculated like this:
you draw an equilateral triangle in the middle with sides or 2r(56mm). The based on pythagorean theorem u know that h=rad(56^2-28^2)=48.497 28+28+h=104.497