Diagonal of the parallelogram divides the parallelogram in to two equal areas.
So area of parallelogram = 2(area of triangle)
According to the given diagram,
AB= 8, AD = 5 and BD = 11
So according to the Heron's formula,
Area of triangle = 
and a, b and c are the three sides of the triangle
Area of triangle ABD =
So, area of parallelogram ABCD = 2(area of triangle ABD)
area of parallelogram ABCD = 2 (18.33)
area of parallelogram ABCD = 36.66
area of parallelogram ABCD = 36.7 sq. units
1. slope of the given line = 1/5
the equation is
(y-2)/(x-(-2))=1/5
x+2=5y-10
x-5y+12=0
2. slope of the given line = -1/6
the equation is
(y-9)/x=6
y-9=6x
y=6x+9