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In known quadrilateral ABCD, angle B = angle d = 90 degree, angle AEC = angle bad, explain the reason of AE flat DC KKKK
∠ DAB + ∠ DCB = 180 °∫ AEC = ∠ bad ∫ AEC + ∠ DCB = 180 °∥ AE ∥ DC (complementary internal angle on the same side, parallel two lines)
As shown in the figure, in ▱ ABCD, it is known that m and N are the midpoint of AB and DC respectively. It is proved that a quadrilateral bmdn is also a parallelogram
∵ quadrilateral ABCD is a parallelogram ∥ ab ∥ DC, ab = DC (parallelogram opposite sides are parallel and equal) (3 points) ∵ m and N are the midpoint of AB and DC respectively. ∵ BM ∥ DN, BM = DN (definition of midpoint) (6 points) ∵ quadrilateral bmdn is also a parallelogram. (a group of parallelogram opposite sides are parallelogram) (10 points)
As shown in the figure, in ▱ ABCD, it is known that m and N are the midpoint of AB and DC respectively. It is proved that a quadrilateral bmdn is also a parallelogram
∵ quadrilateral ABCD is a parallelogram ∥ ab ∥ DC, ab = DC (parallelogram opposite sides are parallel and equal) (3 points) ∵ m and N are the midpoint of AB and DC respectively. ∵ BM ∥ DN, BM = DN (definition of midpoint) (6 points) ∵ quadrilateral bmdn is also a parallelogram. (a group of parallelogram opposite sides are parallelogram) (10 points)
As shown in the figure, in ▱ ABCD, it is known that m and N are the midpoint of AB and DC respectively. It is proved that a quadrilateral bmdn is also a parallelogram
∵ quadrilateral ABCD is a parallelogram ∥ ab ∥ DC, ab = DC (parallelogram opposite sides are parallel and equal) (3 points) ∵ m and N are the midpoint of AB and DC respectively. ∵ BM ∥ DN, BM = DN (definition of midpoint) (6 points) ∵ quadrilateral bmdn is also a parallelogram. (a group of parallelogram opposite sides are parallelogram) (10 points)
RELATED INFORMATIONS
- 1. As shown in the figure, in ▱ ABCD, it is known that m and N are the midpoint of AB and DC respectively. It is proved that a quadrilateral bmdn is also a parallelogram
- 2. As shown in the figure, in the quadrilateral ABCD, points E and F are two points on the diagonal, and be = DF. ① if the quadrilateral aecf is a parallelogram, is the quadrilateral ABCD a parallelogram? Why? ② if the quadrilateral aecf is a diamond, is the quadrilateral ABCD a diamond? Why?
- 3. As shown in the figure, it is known that in ▱ ABCD, e and F are two points on the diagonal BD, be = DF, points g and H are on the extension line of Ba and DC respectively, and Ag = ch connects Ge, eh, HF and FG
- 4. Given that a + B + C = 0, the absolute value of a = 3, the absolute value of B = 5, and the absolute value of C = 7, find the cosine value of the cosine of the cosine angle between the vector 2A + 3b and the vector 3a-b
- 5. Why is the absolute value of a plus B equal to the absolute value of a minus B when a is perpendicular to B,
- 6. Sinacosa = 60 of minus 169 Sina + cosa = 7 of minus 13 A is the second quadrant angle. How can we get Sina = 5 of minus 13 cosa = 1 of minus 13
- 7. As shown in the figure, in the triangular pyramid p-abc, PA = Pb = PC, if PA ⊥ Pb, PA ⊥ PC, Pb ⊥ PC, find the angle between PA and plane ABC
- 8. We know that PA ⊥ Pb, Pb ⊥ PC, PC ⊥ PA in p-abc, and PA = Pb = PC = a, then we find the volume of this pyramid I want the specific process. I must
- 9. Given that the tangent of the curve y = ln (x-2a) + √ (1 + ax) at x = 0 is parallel to the X axis. 1. Find the value of A. 2. Find the tangent and normal equation of the curve at x = 0
- 10. Let the tangent equation of curve y = ax ln (x + 1) at point (0, 0) be y = 2x, then a = () A. 0B. 1C. 2D. 3
- 11. As shown in the figure, in the parallelogram ABCD, AE bisects ∠ bad, CF bisects ∠ BCD, points E and F are on BD, connecting AF and CE, indicating that the quadrilateral aecf is parallel How else can you make a diagonal BD with two points e, f being quadrilateral and aecf being parallelogram
- 12. As shown in the figure, in the parallelogram ABCD, e and F are two points on the diagonal BD, and be = DF, connecting AE, AF, CE and cf. what kind of quadrilateral is the quadrilateral aecf, which shows your truth
- 13. In the parallelogram ABCD, what is the length of CE if the extension line of AE bisector angle bad and intersecting DC is at point E, AB equals 4 and ad equals 9?
- 14. In the parallelogram ABCD, is the midpoint of e-type CD, a point on the edge of F-type BC, and the angle FAE = angle ead, EF and AE perpendicular? Give reasons
- 15. As shown in the figure, in the parallelogram ABCD, e is the midpoint of AD, the intersection of the extension line of CE and Ba and the point F, if BD = 2CD, the verification: ∠ f = ∠ BCF
- 16. In the parallelogram ABCD, ab = KBC, point P is on the diagonal BD, and angle ∠ ape = ∠ bad, PE and BC are compared with point E, and the quantitative relationship between PA and PE is explored
- 17. The edge length of rectangular paper ABCD is ab = 4, ad = 2. Fold the rectangular paper along EF so that point a and point C coincide. After folding, color it on one side (as shown in the figure), the area of the colored part is () A. 8B. 112C. 4D. 52
- 18. (Mianyang, 2011) as shown in the figure, fold a rectangular piece of paper ABCD with a length of 8cm and a width of 4cm so that point a and point C coincide, and the length of crease EF is equal to 2525cm
- 19. When a rectangular piece of paper ABCD is folded along EF, the intersection points of ED and BC are g, D and C at M and N, respectively. If ∠ EFG = 55 °, then ∠ 1=______ °，∠2=______ °．
- 20. As shown in the figure, after a rectangular piece of paper ABCD is folded along EF, points D and C respectively fall at d 'C', the intersection of ED 'and BC is g, if ∠ EFG = 65 degrees Find the degree of ∠ 1 and ∠ 2