The area to the LEFT of the center of the circle is given by
1km x . 8km = .8km^2
Subtract the 1/2 circle area : - 1/2 pi (.8km/2)^2 = - .2513 km^2
.8 - .2513 = .5486 km^2
Total rectangular area is (1+1.4)km x (.8 km) = 1.92 km^2
.5486 km^2/ 1.92 km^2 = .286 = 28.6 % chance of landing in that little area...