As shown in the figure, it is known that in △ ABC, ad and AE are the height and the median line on the edge of BC, ab = 9cm, AC = 7cm, BC = 8cm, respectively

In RT △ abd, ad2 = ab2-bd2, i.e. ad2 = 92 - (4 + de) 2. In RT △ ADC, ad2 = ac2-dc2, i.e. ad2 = 72 - (4-de) 2 ∧ 81 - (4 + de) 2 = 49 - (4-de) 2 ∧ (4 + de) 2 - (4-de) 2 = 32 ∧ 8 · 2DE = 32 ∧ de = 2cm

RELATED INFORMATIONS

1. In △ ABC, high AD and be intersect at h, and BH = AC, then ∠ ABC=______ ．
2. When making excel table, how to calculate the difference between two time numbers and what is the formula
3. Chickens and rabbits are in the same cage. There are 15 more rabbits than chickens. They have 180 feet in total. How many chickens and rabbits are there
4. A desk has three drawers. Each drawer is 50cm in length, 45cm in width and 0.7dm in depth. How many boards should be used to make the desk drawer?
5. Wahaha, the price of mineral water is 1.2 yuan per bottle Wahaha, the price of each bottle of mineral water is 1.2 yuan. Line a and line B offer preferential policies. 10% off for all stores in line a and 20% off for more than 20 bottles in line B. If you are a consumer, which store is more suitable? Why?
6. The truck and bus run from a and B at the same time. The truck runs 35 kilometers per hour and the bus 40 kilometers per hour. After 4 hours, the two cars meet. How many kilometers is the distance between a and B?
7. The speed ratio of a and B is 3:4. It is known that when a finishes one third of the whole journey, there is still a distance from the meeting point 20km, how many km is the distance between AB and ab? Try not to use equations
8. A and B set out at the same time from a and B which are 180 km apart. A rides a bicycle and B drives a car along the same route. It is known that a's speed is 15 km / h and B's speed is 45 km / h How many hours did they meet? How many hours did B arrive at a?
9. A and B leave from ab at the same time. A travels 45 kilometers per hour. B travels 12 hours from B to A. when B meets, a travels four fifths of B. when B meets, how many kilometers does a travel?
10. 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?
11. As shown in the figure, it is known that CD is the height of AB side in △ ABC, and ⊙ o with CD as diameter intersects Ca at point E, and point G is the midpoint of AD. (1) prove that GE is the tangent of ⊙ o; (2) if AC ⊥ BC, AC = 8, BC = 6, find the length of tangent Ge
12. It is known that in △ ABC, ∠ BAC = 120 ° with AB and AC as sides, positive △ abd and positive △ ace are made outward respectively, and M is in AD It is known that in △ ABC, ∠ BAC = 120 ° with AB and AC as sides, make positive △ abd and positive △ ace outward respectively, M is the midpoint of AD, n is the midpoint of AE, and P is the midpoint of BC. It is proved that MP = NP
13. As shown in the figure, △ abd and △ ace are equilateral triangles. What's the use of proving ad = AB and AE = AC in be = CD
14. As shown in the figure, abad = BCDE = ACAE, verification: △ abd ∽ ace
15. As shown in the figure, abad = BCDE = ACAE, verification: △ abd ∽ ace
16. As shown in the figure, abad = BCDE = ACAE, verification: △ abd ∽ ace
17. As shown in the figure, ab ⊥ AC, ab = AC, ad ⊥ AE, ad = AE
18. As shown in the figure, abad = BCDE = ACAE, verification: △ abd ∽ ace
19. As shown in the figure, △ ABC, ab = AC, D is the moving point on AB, DF ⊥ BC is at point F, and Ca extension line is at point E, (1) (2) when point D is on the extension line of Ba, other conditions remain unchanged. (1) is the conclusion still valid? Please give reasons
20. As shown in the figure, ad and AE are the height and middle line of the triangle ABC respectively, and ab = 8, AC = 5. What is the perimeter of the triangle Abe over the triangle ace? What is the relationship between the area of triangle Abe and triangle ace?