<prompt> Kwenye mraba ABCD, pointi E iko upande AD na uhakika F iko upande BC, ili BEEFFD30. Tafuta eneo la mraba ABCD.  <response>: Kuchora mraba na kukagua urefu uliotolewa,asy saizi2inch, 2inch; currentpen fontsize8pt; jozi A 0, 0; nukta A; leboA, A, plain.SW; jozi B 3, 0; nukta B; leboB, B, plain.SE; jozi C 3, 3; nukta C; leboC, C, plain.NE; jozi D 0, 3; nukta D; leboD, D, plain.NW; jozi E 0, 1; nukta E; leboE, E, plain.W; jozi F 3, 2; nukta F; leboF, F, plain.E; lebofrac x3, E--A; lebofrac x3, F--C; lebox, A--B; lebox, C--D; lebofrac 2x3, B--F; lebofrac 2x3, D--E; lebo30, B--E; lebo30, F--E; lebo30, F--D; kuchoraB--C--D--F--E--B--A--D; asy unapata kuwa sehemu hizo tatu zimekata mraba katika sehemu tatu za mlalo sawa. Kwa hivyo, x kuwa urefu wa upande, sqrtx2x3230, au x2x32900. Kutatua kwa x, tunapata x9sqrt10, na x2810.Eneo la mraba ni 810. 