In the triangle ABC, the angle ACB is 90 degrees, AC = BC, ad is the center line of DC side, CE is perpendicular to e, and the extension line of CE intersects AB at F Find the value of (1) AE ratio de and (2) Tan angle bad
The first problem is: Method 1 ∵ AC ⊥ CD, CE ⊥ ad, ∵ CAE ⊥ DCE. [the same is the residual angle of ⊥ ADC] ∵ ace ∽ CDE, ∵ ace area / △ CDE area = (AC / AD) ^ 2. AC = BC, CD = BC / 2, ∵ AC = 2CD, ∵ ace area / △ CDE area = 4
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- 1. It is known that: as shown in the figure, in △ ABC, AC = BC, ∠ ACB = 120 °, CE is perpendicular to AB and D, and de = DC
- 2. As shown in the figure, in the triangle ABC, ab = AC, the angle a = 120 ° de bisects AB and BC vertically in D, e
- 3. In △ ABC, ab = AC, ∠ a = 120 °, D is the midpoint of AB, crossing D as the vertical bisector of AB and crossing BC at e. the proof is EC = 2be
- 4. It is known that in △ ABC, be = CE, ∠ DBC = ∠ ACB = 120 °, BD = BC, CD intersection AB is at point e., and de = 3ce is proved
- 5. In non isosceles triangle ABC, D is the midpoint of BC and F is the midpoint of ab. the correct conclusion is that a AE: ad = 1:3, B △ abd is all equal to △ ADC, C △ abd is similar △ADC D △AEF=△CED
- 6. In the isosceles triangle ABC, the angle a is equal to 20 degrees, AB is equal to AC, D is on AC, and ad is equal to BC. Find the size of the angle abd
- 7. In the isosceles triangle ABC, AB equals AC equal to 13, BC equal to 10, D is the midpoint of AB, do de through D, perpendicular to AC and E, find de?
- 8. As shown in the figure, in △ ABC, ab = AC, ∠ a = 36 °, BD and CE are the bisectors of △ ABC and △ BCD, respectively, then the isosceles triangle in the figure has______ One
- 9. In the triangle ABC, ab = AC, point D is on AC. when the angle a is equal to what degree, the triangle abd and the triangle BCD are isosceles triangles There is no graph, just let you find the angle a how many degrees
- 10. In △ ABC and △ ACD, ∠ ACB = ∠ ADC = 90 °, AC = 5, ad = 4. When BC is equal to what, △ ABC is similar to △ ADC? Explain your reason Picture: a right triangle on the left is placed upright, with vertex a, bottom left B, bottom right C, ∠ C as right angle, and a right triangle on the right is smaller than △ ABC, one side is collinear with AC, two outer sides are right angles with D, ∠ d. A is also the vertex of the right triangle, and C is another point except vertex and right angle Answer before April 10
- 11. As shown in the figure, in △ ABC, ad ⊥ BC, CE ⊥ AB, D and e respectively, ad and CE intersect at point h, please add an appropriate condition:______ So that △ AEH ≌ △ CEB
- 12. In triangle ABC, ad intersects BC at point D, CE is perpendicular to ad at point E, connect be, ∠ ABC = 45 degrees, ∠ ADC = 60 degrees, DC = 2bd, try to find the degree of ∠ C
- 13. In the triangle ABC, the angle a = 90 degrees, the bisector of angle c intersects at point D, the known angle DCB = 2, the degree of angle ADC is calculated
- 14. As shown in the figure, in △ ABC, the bisector of ∠ a = 90 ° intersects AB at D. if ∠ DCB = 2 ∠ B, calculate the degree of ∠ ADC
- 15. As shown in the figure, △ ABC, angle a = 90 ° and bisector of angle c intersects AB at D. given angle DCB = 2 angle B, calculate the degree of angle ADC
- 16. If the line y = x + 2 passes through a focus and a vertex of the ellipse x2a2 + y2b2 = 1 (a > b > 0), then the eccentricity of the ellipse is 0___ .
- 17. As shown in the figure RT △ ABC, ab = AC = 1, make an ellipse with point C as a focus, so that the other focus of the ellipse is on the edge of AB, and the ellipse passes through two points a and B, then the focal length of the ellipse is______ .
- 18. In RT △ ABC, ∠ C = 90 ° and ∠ a = 30 °, then a and B are the focus, and the eccentricity of ellipse passing through point C is the same______ .
- 19. One or two cars have traveled 156 kilometers in the first three hours from place a to place B. to find such a speed, it will take five hours from place a to place B. how many kilometers are there between the two places?
- 20. 1. A and B drive from two places 324km apart at the same time and meet on the way after 6 hours. The speed of a is 80% of that of B 2. Master Zhang made a batch of parts, which accounted for 40% of the total on the first day. If he made 12 more parts, he would finish two-thirds of the total. How many parts are there in total?