Known: as shown in the figure, points B, e, C, f are on the same line, ab = De, AC = DF, be = CF

It is proved that: ∵ be = CF, ∵ BC = EF, ab = De, AC = DF, ≌ ABC ≌ def, ≌ B = ≌ def, ∥ ab ∥ de (the same angle, two lines parallel)

RELATED INFORMATIONS

1. Known: as shown in the figure, points B, e, C, f are on the same line, ab = De, AC = DF, be = CF
2. As shown in the figure, in △ ABC, D is the point on AB, DF intersects AC at e, de = Fe, AE = CE, what is the positional relationship between AB and CF? Prove your conclusion
3. It is known that in diamond ABCD, e and F are points on AB and ad respectively, and AE = AF. verification: CE = CF
4. Given that ab = 1, CD = 2, the circumscribed sphere radius r = 3 in the tetrahedral ABCD, the maximum volume of the tetrahedral ABCD can be obtained
5. M ^ 2 + M-1 = 0, find the value of m ^ 3 + 2m ^ 2 + 2012
6. If the solution set of inequality | x2-8x + a | ≤ x-4 is [4,5], then the value of real number a is equal to______ ．
7. In triangle ABC, Pb is vertical to AB, PR is vertical to BC, PS is vertical to AC, and PQ = 6, PR = 8, PS = 10 Q. R and s are on three sides
8. In rectangular ABCD, the diagonal lines AC and BD intersect at O, ∠ AOD = 120 °, BC = 3cm under the root sign. Calculate the length of AC and the area of rectangular ABCD
9. The two diagonals of rectangle ABCD intersect at point O. given that the angle AOD is equal to 120 ° and ab is equal to 2.5cm, find the length of the diagonal of rectangle?
10. In rectangle ABCD, two diagonals intersect at point O, if ∠ AOD = 120 ° AB = 2, find the perimeter of rectangle
11. As shown in the figure, ab = CD, DF ⊥ AC in F, be ⊥ AC in E, DF = be, verification: AF = CE
12. It is known that: as shown in the figure, AC bisects ∠ bad, CE ⊥ AB in E & nbsp; CF ⊥ ad in F, and BC = DC
13. As shown in the figure, ab | DC, ad | BC, points E and F are on AB and DC respectively, and be = DF, AF = CE
14. As shown in the figure, AC ⊥ BC, ad ⊥ BD, ad = BC, CE ⊥ AB, DF ⊥ AB, perpendicular feet are e and f respectively, so, CE = DF?
15. The vertical line CE is drawn from the vertex C of rectangle ABCD to the diagonal BD, and the perpendicular foot is e. if CE is divided into two angles with ∠ C being 1:5, then ∠ ace=
16. It is known that in trapezoid ABCD, ab ∥ CD, ad = DC = BC = 4 ∠ DCB = 120 ° CE ⊥ AB, the area of AC ⊥ BC and trapezoid is calculated
17. Known: as shown in the figure, EF is the median line of trapezoidal ABCD, AF bisector angle DAB verification: ad = 2ef There is no picture
18. As shown in the figure: AE is the bisector of ∠ BAC in square ABCD, AE intersects BD and BC at f and e respectively, AC and BD intersect at O, verification: of = 12ce
19. As shown in the figure, in ▱ ABCD, if the bisector AE of ∠ bad intersects BC at e, ad = 6, EC = 2, then the length of CD=______ ．
20. Find the normal vector of the plane passing through points a (0,0,0), B (1,4,0), C (0,2,0)