As shown in the figure, △ ABC, D, e and F are the points on AB, BC and AC respectively. DF ‖ BC and ef ‖ AB are known. Please add a condition:______ To make △ ADF ≌ FEC

If AF = FC, DF ∥ BC, EF ∥ AB are known, then the congruence can be determined by AAS if ADF = ABC = FEC and AFD = C. similarly, if DF = EC or ad = FC is added, the congruence can be determined by AAS

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1. If AB = 3 and EF = 4, what is AC equal to?
2. Given that the angle ABC is equal to the angle def, AB is equal to 3, AC is equal to 5, if the perimeter of the angle DEF is even, what is the length of ef?
3. AB: de = BC: EF = CA: FD = 6:5, the difference between the perimeter of triangle ABC and triangle DEF is 4, how much is the perimeter of ABC and def?
4. AB: de = BC: EF = CA: FD = 6:5, the difference between the perimeter of triangle ABC and triangle DEF is 4, how much is the perimeter of ABC and def?
5. In △ ABC and △ def, ABDE = BCEF = CAFD = 23, the perimeter of △ ABC is 13cm, then the perimeter of △ DEF is 13cm______ ．
6. If △ ABC ≌ Δ DEF is known, if the circumference of △ ABC is 38, ab = 8, BC = 12, then de =? EF =? DF =? Who can write down the process of finding DF,
7. It is known that △ ABC is all equal to △ def. If the circumference of △ ABC is 32, and ab = 8, BC = 2, try to find out the lengths of De, EF, DF and DF respectively Big brother, big sister, what, do me a favor
8. In △ ABC and △ def, AB / de = BC / EF = AC / DF = = 4, find the ratio of the perimeter of △ ABC to that of △ def Utilization ratio
9. It is known that △ ABC ≌ Δ def, if the perimeter of △ ABC is 32ab = 9, BC = 11, then de =, EF =, DF=
10. It is known that △ ABC ∽ def, the perimeter of △ ABC and △ def are 20cm and 25cm respectively, and BC = 5cm, DF = 4cm. The lengths of EF and AC are calculated
11. It is known that a, F, C and D are on the same straight line, AC = DF, ab ‖ De, EF ‖ BC. Try to explain: (1) ABC ≌ def; (2) CBF = FEC
12. As shown in the figure, four points a, F, C and D are known to be on the same straight line, AF = CD, ab ‖ BC and ef ‖ BC. The formula shows that (1) △ ABC ≌ △ def; (2) angle CBF = angle FEC
13. The vertex of quadratic function y = AX2 + BX + C is represented by ABC!
14. In the RT triangle ABC, the angle c is equal to 90 degrees, ab = 13cm, BC-AC = 7cm
15. In RT △ ABC, the angle ACB = 90 °, CD ⊥ AB in D, ab = 13cm, the sum of AC and BC is equal to 17cm
16. How are the capacitance units f farad, MF nanofa, NF nanofa, PF Pico FA converted?
17. The ammeter is refitted into a voltmeter in series with a large resistor to divide the voltage. Why can it become a voltmeter? What is the meaning of the value measured by the ammeter? How to calculate the voltage with this value?
18. Connect two fixed value resistors in series to both ends of the power supply with voltage of u, the power consumed by R1 is P1, and the power consumed by R2 is 3P1 A. The ratio of voltage between R1 and R2 in series is 3:1b. The power consumed by R1 in parallel is 16p1c. The ratio of current through R1 and R2 in parallel is 1:3d. The total power consumed by two resistors in parallel is 163p1
19. The "pz220 & nbsp; 40" bulb works on a 220 volt circuit______ The power consumption per hour is 1 kilowatt hour, and the power of the circuit connected at 110 V is 0______ The rated power is______ Tile
20. The price of type a refrigerator sold in shopping malls is 2190 yuan per unit, and the daily power consumption is 1 degree, while the price of type B energy-saving refrigerator is 10% higher than that of type a refrigerator, but the daily power consumption is 0.55 degree? (calculated according to the service life of 10 years, 365 days per year and 0.40 yuan per kilowatt hour)