first, area av all shapes is the same if yu muev it around ("translate" in krat speek)
so add 8 tu the x av all 3 points & add 3.4 tu y av all 3 & yu get
(+7.9,0) (0.1,0) (7.9,10.2)
x-part...length go from 0.1 tu 7.9=7.8
y-part...wide go from 0 tu 10.2...wide=10.2
area=length*wide=7.8*10.2=79.56