![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
1993 + ABC = 2dde abcd-cdc = ABC what numbers do a, B, C and e represent? ABCD represents a number, but not the same number
According to the meaning of the title, 1993 + abbc = 2dde, thousand digits 1 + a = 2, so a = 1 or a = 0, if a = 1, B + 9 can't carry, so B = 0
The preliminary conclusion is as follows
```1993
``+100C
--------
```2DDE`````(1)
```10CD
``-`CDC
--------
````10C``````(2)
If we observe the ten digit number of formula (2), the result of C-D is zero, and because C and D cannot be equal, we must borrow one digit
1、 That is, D + 1 = C, the ten digit number is not borrowed from the hundred digit number, so C = 9, d = 8, and the formula (1) 1993 + 1009 and the result are brought in
The thousand digit number is 2, so a = 0
If a = 0, then bcd-cdc = BC, so B = C + 1, d = C + C or 1D = C + C, then D is even and D is not equal to 0,
So there is no solution
Is it over the wrong number
In the formula on the right, ABCD stands for
a=1,b=0,c=9,d=8
As shown in the figure, in the parallelogram ABCD, the bisector of ∠ ABC intersects CD at point E, and the bisector of ∠ ADC intersects AB at point F. try to judge whether AF and CE are equal, and explain the reason
AF = CE. The reasons are as follows: ∵ quadrilateral ABCD is a parallelogram, ∵ ad = CB, ∵ a = C, ∵ ADC = ABC, and ∵ ADF = 12 ≌ ADC, ∵ CBE = 12 ≌ ABC, ∵ ADF = CBE. In △ ADF and △ CBE,
RELATED INFORMATIONS
- 1. As shown in the figure, in the parallelogram ABCD, the bisector of ∠ ABC intersects CD at point E, and the bisector of ∠ ADC intersects AB at point F. try to judge whether AF and CE are equal, and explain the reason
- 2. In △ ABC, ab = BC, AB is the height of BC side, AE is the bisector of ∠ BAC, ead = 48 ° to find ∠ ACD
- 3. It is known that BD is the middle line of the triangle ABC, and the perimeter of the triangle abd is 2cm longer than that of the triangle BCD. If the perimeter of the triangle ABC is 18cm and AC = 40cm, the lengths of AB and BC are obtained
- 4. In the triangle ABC, D and E are the points of the edges of AC and BC respectively, and EC: EB = 1 / 3. It's troublesome to find the values of BC: be, DC: AC and ad: AC
- 5. In the triangle ABC, ab = AC, angle a = 120 degrees, D is the midpoint of BC, De is perpendicular to AB and E, and the ratio of AE to EB is calculated
- 6. As shown in the figure, be and CF are the heights of △ ABC, M is the midpoint of BC, BC = 10, EF = 5, root 2, and find the area of triangle EFM kuaidiann
- 7. As shown in the figure, at the isosceles right angle △ ABC, ∠ C = 90 °, AC = BC, D is any point on AB, AE ⊥ CD is at e, BF ⊥ CD intersects the extension line of CD at F, CH ⊥ AB is at h, Give AE to g, verify: CE = BF
- 8. As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree
- 9. As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree
- 10. As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree
- 11. What is the surface area of a regular pyramid whose vertices are on the same sphere, whose height is 3 and volume is 6
- 12. Given the cube abcd-a1b1c1d1 with side length a, O is the center of the bottom a1b1c1d1, e is a point on the edge A1B1, and the length of AE + EO is the smallest, then the minimum value is Why do I think it's a got it.. I always calculate a1e + E0 depressed
- 13. If you take any point P in the cube abcd-a1b1c1d1 with edge length a, then the probability that the distance between P and point a is not greater than a is: I know everything else, but why is it 1 / 8 of the volume of a sphere centered on a, I think it is 1 / 4!
- 14. In the cube abcd-a1b1c1d1 with edge length a, randomly take the point m in the cube. (1) find the probability that the distance between M and surface ABCD is greater than a / 3 (2) Find the probability that the distance between M and face ABCD and face a1b1c1d1 is greater than a / 3
- 15. In the triangular pyramid p-abc, PA ⊥ plane ABC, ab ⊥ AC, D, e and F are the midpoint of PA, Pb and PC respectively, connecting De, DF and ef (1) To prove the parallel plane ABC of plane def (2) If PA = BC = 2, the cosine value of dihedral angle a-ef-d is obtained when the volume of triangular pyramid p-abc reaches the maximum
- 16. As shown in the figure, in the triangular pyramid p-abc, plane ABC is perpendicular to plane APC, ab = BC = AP = PA = radical 2, angle ABC = angle APC = 90 degrees Q: how to find the area of triangle PBC?
- 17. In the regular tetrahedron ABCD with edge length of 1, e and F are the midpoint of AD and BC, respectively RT
- 18. In tetrahedral a-bcd with equal edge length, e and F are the midpoint of AD and BC respectively. The cosine value of the angle formed by the straight lines AF and Ce on the different planes is obtained
- 19. As shown in the figure, in rectangular ABCD, fold the triangle BCD along BD to the position of triangle BDE, be and ad intersect at o point, and connect AE (1) Proof: the quadrilateral ABDE is isosceles trapezoid; (2) If the angle DBC = 30 ° AB = 2, find the area of quad ABDE
- 20. As shown in the figure, fold a rectangular piece of paper ABCD along AF to make point B fall at B ′. If ∠ ADB = 20 °, then how many degrees should ∠ BAF be to make ab ′‖ BD?