ABCD is a square, the area of △ DEF is 6 square cm larger than that of △ ABF, and CD is 4 cm long

The area of triangle BCE is: 4 × 4 + 6, = 16 + 6, = 22 (square centimeter), the base ce of triangle BCE is: 22 × 2 △ 4 = 44 △ 4, = 11 (centimeter), the length of De is: 11-4 = 7 (centimeter). Answer: the length of De is 7 centimeter

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1. 22. Square ABCD, the area of triangle DEF is 6 square centimeters larger than that of triangle ABF. CD is 6 cm long, what is the length of de
2. The side length of square ABCD is 20, CD is extended to e, connecting be. If the area of triangle ABF is 30 larger than that of triangle def, the length of De is calculated
3. As shown in the figure, the quadrilateral ABCD is a rectangle, BC = 15cm, CD = 8cm. The area of triangle ABF is 30cm larger than that of triangle def. Find the length of de
4. The side length of the bottom of the hexagonal prism is equal to 1, and the side length is 2. After the side of the prism is expanded along a side edge, the area of the side expansion is calculated
5. The area of one side of an oblique triangular prism is 10. The distance between the side and the opposite edge is equal to 6. The volume of the prism can be calculated
6. The bottom of a straight prism is a square with a side length of 3. How much is the side area of the straight prism and how much is the total area It's a square with two sides
7. If the figure is the front view and left view of a regular hexagonal prism, then a = () A. 23B. 3C. 2D. 1
8. If the front view and top view of a triangular prism with equal length of all edges are square and regular triangle respectively, the left view is square______ ．
9. If the front view and top view of a triangular prism with equal edge lengths are square and regular triangle respectively, then the left view is () A. Rectangle B. square C. diamond D. regular triangle
10. If the front view and top view of a triangular prism with equal length of all edges are square and regular triangle respectively, then the left view is? If the front view and top view of a triangular prism with equal length of all edges are square and regular triangle respectively, then the left view is () A. Rectangle B. square C. diamond D. regular triangle Why?
11. The area of square a, B, C and D is 144 square centimeters. Efgh is the middle points of four sides respectively, which are successively connected to form a small square, and the side length surface of the small square is calculated
12. Two congruent squares ABCD, aefg, with vertex a, CD and EF in common, intersect at point p; PC = pf; what kind of special quadrilateral with vertex e, C, F and D needs to be proved
13. As shown in the figure, EF is the double fold line of square ABCD, and the vertices of ∠ A and ∠ B coincide on EF. At this time, how many degrees is ∠ DHG?
14. As shown in the figure, the vertex e of the square aefg is on the edge CD of the square ABCD; the extension of ad intersects EF at the H point. (1) try to explain: △ AED ∽ EHD; (2) if e is the midpoint of CD, find the value of hdha
15. Take a point a on De, take ad and AE as the square side, make square ABCD and square aefg on the same side, connect DG, be, then the line segment DG and be meet De De = be and DG is perpendicular to be 1. If the square aefg is rotated a degree clockwise around point a, that is, the angle bag = a degree, is the conclusion still valid 2. Let the edge length of the square ABCD and aefg be 3 and 2, and the area of the closed figure enclosed by the line segments BD, De, eg and GB be s. when a changes, does s have the maximum value? If so, calculate the maximum value of a and the corresponding value of A
16. The edge CD of square ABCD connects be and DG on the edge ce of square ECGF;
17. The edge CD of square ABCD connects be and DG on the edge ce of square ECGF. (1) observe the size relationship between be and DG and prove the conclusion. (2)
18. As shown in the figure, it is known that the side length of square ABCD is 10 cm, point E is on side AB, and AE = 4 cm. If point P moves from point B to point C at a speed of 2 cm / s on line BC, and point Q moves from point C to point D on line CD, let the motion time be T seconds. (1) if the motion speed of point q is equal to that of point P, after 2 seconds, are △ BPE and △ CQP identical? Please explain the reason; (2) if the velocity of point q is not equal to that of point P, then when t is the value, it can make △ BPE and △ CQP congruent; at this time, what is the velocity of point q
19. Let the side length of the square ABCD be 6, and rotate 30 degrees clockwise around point a to get the square aefg, where the side FG and BC intersect at h, and find the length of BH
20. As shown in the figure, rotate square ABCD around point a clockwise to get square aefg, edge FG and BC intersect at point h. verification: Hg = Hb