As shown in the figure, in square ABCD, e is a point on the edge of CD, f is a point on the extension line of BC, CE = CF
It is proved that: ∵ quadrilateral ABCD is a square, ∵ BC = DC, ≌ BCD = ≌ DCF = 90 ° in △ BCE and △ DCF, ≌ BC = DC, ≌ BCD = ≌ DCF = 90 ° CE = CF, ≌ BCE ≌ DCF (SAS), ≌ be = DF
RELATED INFORMATIONS
- 1. As shown in the figure, in square ABCD, e is a point on CD, f is a point on BC extension line, CE = cf. (1) prove: △ BCE ≌ △ DCF; (2) if ∠ BEC = 60 °, calculate the degree of ∠ EFD
- 2. E is on CD, f is a point on the extension line of BC, CE = CF (1) proves that triangle BCE congruent triangle DCF (2) ∠ FD E is on CD, f is a point on BC extension line, CE = CF (1) Proof of triangle BCE congruent triangle DCF (2) How much is ∠ FDC = 30 ° and ∠ bef = 0
- 3. As shown in the figure, in the isosceles trapezoid ABCD, ad = 4cm, BC = 8cm, e is the midpoint of the waist AB, CE divides the trapezoid circumference into two parts, the difference is 3cm, and calculates the trapezoid circumference
- 4. As shown in the figure, in the isosceles trapezoid ABCD, ad = 4cm, BC = 8cm, e is the midpoint of the waist AB, CE divides the trapezoid circumference into two parts, the difference is 3cm, and calculates the trapezoid circumference
- 5. As shown in the figure, in the isosceles trapezoid ABCD, ad = 4cm, BC = 8cm, e is the midpoint of the waist AB, CE divides the trapezoid circumference into two parts, the difference is 3cm, and calculates the trapezoid circumference
- 6. As shown in the figure, in the isosceles trapezoid ABCD, ad = 4cm, BC = 8cm, e is the midpoint of the waist AB, CE divides the trapezoid circumference into two parts, the difference is 3cm, and calculates the trapezoid circumference
- 7. In the trapezoidal ABCD, ab = 8, ad = 5, CD = 6, BC = 15. Point E is on the bottom BC, and point F is on the waist CD. EF bisects the area and perimeter of ABCD at the same time to find the length of CE
- 8. In the isosceles trapezoid ABCD, AD / / BC, assuming BC = 4, ad = 8, angle a = 45 degrees, the area of the trapezoid is calculated
- 9. As shown in the figure, in the trapezoidal ABCD, ad ‖ BC, ∠ B = 90 °, ab = 14cm, ad = 18cm, BC = 21cm, point P starts from point a, moves at 1cm / s along side ad to point D, and point Q starts from point C, moves at 9cm / s along side CB to point B. If one point moves to the end point, the other point stops. If P and Q start at the same time, can a quadrilateral PQCD become an isosceles trapezoid? If so, how many seconds? If not, please give reasons
- 10. As shown in the figure, in the trapezoidal ABCD, ad ‖ BC, ∠ B = 90 °, ab = 4cm, ad = 18cm, BC = 21cm, point P starts from point a, moves 2cm / s along edge ad to point D, point Q starts from point C, moves 6cm / s along edge CB to point B, P and Q start at the same time, if one point moves to the end point, the other point stops=______ Cm; 2______ Second, PQ = CD
- 11. As shown in the figure, in the square ABCD, f is a point on CD, AE ⊥ AF, point E is on the extension line of CB, EF intersects AB at point G, proving: de · FC = BG · EC
- 12. As shown in the figure, the point E is on the diagonal BD of the square ABCD, and be = AB, EF ⊥ BD, EF and CD intersect at the point F to prove de = EF = FC
- 13. As shown in the figure, in square ABCD, e is a point on the edge of BD, and be = BC, EF is perpendicular to BD, intersecting CD with F
- 14. As shown in the figure, take a point E on the diagonal BD of square ABCD, make be = BC, make ef vertical BD, intersect CD with F. the line segment De is equal to EF and FC? Why?
- 15. How to calculate the electricity consumption of refrigerator in an hour What is the formula?
- 16. Suppose that two resistors with resistance values of 1 ohm and 10 ohm are connected in parallel, and their equivalent resistance is R1. Three resistors with resistance values of 1 ohm, 10 ohm and 100 ohm are connected in parallel After (connecting), the equivalent is set to R2 A. R1 > R2 B. R1 < R2 C. R1 = R2 D. cannot be determined
- 17. In the series circuit of constant value resistor, sliding rheostat and ammeter, the voltmeter is connected in parallel at both ends of the resistor. If the voltage expression is 0 during the experiment, If the current indicator is 0 and the voltage indicator increases suddenly, what fault will happen?
- 18. In parallel circuit, if one resistance decreases, what is the current shared by this resistance and what is the voltage, resistance and power of the other resistance in parallel In a series circuit, if one resistance decreases, what is the current shared by this resistance, and what is the voltage, resistance and power of the other resistance in series
- 19. 1) 2) what is the function of resistance?
- 20. What is the maximum allowable voltage and current of a 2000 ohm resistor with a rated power of quarter watt?