ABCD is a parallelogram, e and F are the midpoint of AD and BC respectively

Because the quadrilateral ABCD is a parallelogram, so Ed parallel BF, BC = ad 1, and because e, f are the midpoint, so Ed = BF, we know ed parallel BF, so the quadrilateral bfde is a parallelogram, so Ed parallel BF

It is known that: as shown in the figure, in the quadrilateral ABCD, AB > ad, AC bisects ∠ DAB, ∠ B + ∠ d = 180 °. Verification: CD = CB

As shown in the figure, in the quadrilateral ABCD, AC bisects ∠ DAB, if AB > ad, DC = BC

Prove: as shown in the figure, cut ad = AF on AB, connect FC. ∵ AC, divide ∵ DAB equally, ∵ 1 = ∵ 2, in △ ADC and △ AFC, ad = AF ≌ 2Ac = AC, ≌ ADC ≌ AFC (SAS), ∵ d = ≌ 4, CD = CF. in addition,

RELATED INFORMATIONS

1. In the quadrilateral ABCD, the diagonal AC bisects ∠ bad, AB > ad
2. It is known that e is the edge of the parallelogram ABCD, AB extends to the upper point, de intersects BC with F. proof: the area of the triangle ABF is equal to the area of the triangle efc Mathematics in grade two
3. In the parallelogram ABCD, AE ⊥ BC in E, AF ⊥ CD in F, ∠ BAE = 30 °, be = 2, CF = 1, (1) find the area of triangle ECD, (2) Find the length of EG
4. As shown in the figure, in isosceles trapezoid ABCD, ad ‖ BC. AB = DC, e is the midpoint of BC, connecting AE and De, proving: AE = De
5. As shown in the figure, the diagonals AC and BD of rectangle ABCD intersect at O, AE ‖ BD, de ‖ AC
6. As shown in the figure: given rectangular ABCD, AC and BD intersect at O, AE ‖ BD, de ‖ AC. verification: OE ⊥ ad
7. As shown in the figure, the quadrilateral ABCD is inscribed in the circle, the diagonal AC and BD intersect at the point E, f is on AC, ab = ad, ∠ BFC = ∠ bad = 2 ∠ DFC. Verification: (1) CD ⊥ DF; (2) BC = 2CD
8. Given that ad is parallel to BC and E is the midpoint of Cd in trapezoidal ABCD, is the area of trapezoidal ABCD twice that of triangular Abe
9. As shown in the figure, in the trapezoidal ABCD, ab ‖ CD is known, and point E is the midpoint of BC. If the area of △ DEA is S1 and the area of trapezoidal ABCD is S2, then the quantitative relationship between S1 and S2 is______ ．
10. In diamond ABCD, AD / / BC, ab = CD, e is the midpoint of the bottom BC, connecting AE and de I'm sorry. I didn't pay attention to it It's in ABCD
11. In the parallelogram ABCD, there is a point E on the side of DC, which connects AE. The point F is on the side of AE, and connects B. It is proved that the triangle ABF is similar to the triangle EAD Angle BFE is equal to angle C
12. In square ABCD, point G starts from point C and moves along CB; point h starts from point a and moves along Ba, and two points move at the same speed and stop at the same time
13. In quadrilateral ABCD, ad = BC, AE, CF are perpendicular to BD, be = DF. It is proved that quadrilateral ABCD is parallelogram I can't find the last condition in the verification. Please give me some advice. Thank you
14. Take a point G on the extension line of one side of the square ABCD and connect it with a, intersect BC at point F, connect diagonal BD and intersect AF at point E. AE = 5, AF = 3 are known, and calculate the length of FG chart
15. As shown in the figure, in ladder ABCD, ab ‖ CD, e is the midpoint of DC, the line be intersects AC at F, and the extension line of ad intersects g; verification: EF · BG = BF · eg
16. As shown in the figure, ad ∥ BC in ladder ABCD, point E is the midpoint of edge ad, connecting be with AC at point F, the extension line of be with CD at point G, verify Ge / GB = AE / BC
17. In the quadrilateral ABCD, BD bisects ∠ ABC, AC ⊥ BD at R, PQ intersects BC and ad at points Q and P respectively, and ∠ bad = ∠ BQP
18. As shown in the figure below, the area of rectangle ABCD is 12 square decimeters, so the area of circle is () square decimeters Well, there is no picture. Let's give a brief description There is a circle, no matter how big, half of it (that is, a semicircle). Draw a rectangle on the semicircle. The length of the rectangle is equal to the diameter of the circle. Then say that the area of the rectangle is 12 square decimeters. Tell the area of the whole circle. Thank you!
19. The perimeter of parallelogram ABCD is 75cm, the height is 14cm with BC as the bottom (as shown in the figure); the height is 16cm with CD as the bottom. Calculate the area of parallelogram ABCD
20. In the trapezoidal ABCD, point P starts from point a and moves along the edge of ad to point d at a speed of 1cm / s, and point Q starts from point C and moves along CB to point B at a speed of 2cm / s. if points P and Q start from two points at the same time, when one of them reaches the end point, the other stops moving. (1) what is the value of T when trapezoidal pbqd is a parallelogram? (2) What is the value of T when trapezoid pbqd is isosceles trapezoid?