Find the area of the trapezoid shown below

9.42119.423.518.8[Graphs generated by this script: initPicture(-1,5.5,-1,5.5);path([[0,0],[1,4],[3,4],[5,0],[0,0]]);text([2,4],'9.4','above');text([4,2],'21','right');text([0.5,2],'19.4','left');text([2.5,0],'23.5','below');stroke='red';fontfill='red';line([1,0],[1,4]);text([1,2],'18.8','right');]