As shown in the figure, in the right triangle ABC, the quadrilateral efbh is a square, ab = 21cm, BC = 28cm, AC = 35cm, ED is perpendicular to AC, ed = 8.4cm, what is the area of the square efbh?

As shown in the figure, in the right triangle ABC, the quadrilateral efbh is a square, ab = 21cm, BC = 28cm, AC = 35cm, ED is perpendicular to AC, ed = 8.4cm, what is the area of the square efbh?

Connect AE, CE, set the EF as X, AF = 21-x, ch = 28-x, ch = 28-x, ch = 21-x, AF = 21-x, AF = 21-x, AF = 21-x, AF = 21-x, AF = 21-x, AF = 21-x, AF = 21-x, AF = 21-x, AF = 21-x, Ch = 28-x, ch = 28-x, 28-x, 35 × 8.4 × 8.4 (21-x-21-21-21-x) and 35 × 8.4-8.4-4.4 (21-21-x-21-21-x) x (21-21-21-x) x (21-21-21-x) x (21-21-21-21-21-21-21-21-x) x) x (21-21-21-x) x) x, 35 (21-x, 35 × 8, 35 × 8.4, 35 × 8.4 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;                   147+24.5x=294，                                 24.5x=147，     && nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & X = 6; the area of square efbh is: 6 × 6 = 36 (square centimeter), a: the area of square efbh is 36 square centimeter