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In triangle ABC, the bisector of AB = AC = 3 BC = 2 ∠ ABC intersects the parallel line of BC at d to find the area of triangle abd
3,3,2 triangles determined
High square 3 * 3-1 * 1 = 8
Area: 2 * root 8 divided by 2
It's two root two
As shown in the figure, the bisector of the inner angle ∠ ABC of △ ABC intersects with the bisector of the outer angle ∠ ACG at point D, and the parallel line of BC crosses AB to e and AC to F through point D. try to judge the relationship between EF and be, CF, and explain the reason
EF = be-cf. prove: ∵ BD bisection ∵ ABC, ∵ abd = ∵ DBC. Also ∵ ed ∥ BC, ∵ EDB = ∵ DBC; ∵ abd = ∵ EDB, ∵ be = ed; similarly prove: CF = FD; ∵ EF = ed-fd, ∵ EF = be-cf
In △ ABC, the bisector of ∠ C intersects AB at D, and the bisector of BC intersects AC at e through D. given BC = a, AC = B, the length of De can be obtained
∵ de ∥ BC, ∥ 1 = ∥ 3. And ∥ 1 = ∥ 2, ∥ 2 = ∥ 3DE = EC, from △ ade ∥ ABC, ∥ DEBC = aeac, DEA = B − DEB, B ∥ de = AB-A · De, so de = ABA + B
RELATED INFORMATIONS
- 1. As shown in the figure, △ ABC, D is on AB, ad = BD = CD, de ∥ AC, DF ∥ BC
- 2. As shown in the figure, in the isosceles right triangle ABC, ∠ ACB = 90 °, point D is the midpoint of BC, and the isosceles right triangle DCE is made with CD as the side, where the angle DCE = 90 ° CD = CE, link AE, the quantitative relationship between AE and BD, explain the reason
- 3. AB is the diameter of ⊙ o, C is on ⊙ o, BP is the middle line of △ ABC, BC = 3, AC = 62, find the length of BP
- 4. In RT triangle ABC, ad is the middle line on hypotenuse BC. How to prove ad = 1 / 2BC?
- 5. If BC = 32 and BD ∶ CD = 9 ∶ 7, then the distance between point D and ab is? 2. If y = 2, the distance between point D and ab is? 2 Please write down the process
- 6. As shown in the figure, CD is the height on the hypotenuse of RT △ ABC, the bisector of a intersects CD at h, and the bisector of BCD intersects G
- 7. In the triangle ABC, angle ACB = 90 degrees, angle B = 35 degrees, CD is the height of hypotenuse ab. find the best BCD and the degree of angle A
- 8. As shown in the figure, in the right angle △ ABC, CD is the height on the hypotenuse AB, ∠ BCD = 35 °, find: (1) the degree of ∠ EBC; (2) the degree of ∠ a
- 9. It is known that: as shown in the figure, one side De of rectangular defg is on the side BC of △ ABC, the vertices g and F are on the sides AB and AC respectively, ah is the height of the side BC, ah and GF intersect at the point K, BC = 12, ah = 6, EF: GF = 1:2 are known, and the perimeter of rectangular defg is calculated
- 10. In the triangle ABC, ad is the middle line on the edge of BC, ad bisects ∠ a, and makes de ⊥ AB, DF ⊥ AC through point D. prove: be = CF
- 11. As shown in the figure, go through the center of gravity o of △ ABC (the intersection of the three midlines) and make a parallel line of BC, intersecting AB at D and AC at E. then the area ratio of △ ade to △ ABC is () A. 1：2B. 2：3C. 1：3D. 4：9
- 12. Make parallel lines of AB, BC and AC respectively through a point P in the triangle ABC Drawing
- 13. As shown in the figure, in △ ABC, the points D and E are on the side of BC, and ∠ B = ∠ bad, ∠ C = ∠ CAE, BC = 8cm is known, find the perimeter, line and speed of ADE
- 14. It is known that in RT △ ABC, ∠ C = 90 ° CoSb = 23, then the value of SINB is () A. 253B. 53C. 255D. 55
- 15. Known: as shown in the figure, RT △ ABC ≌ RT △ ade, ∠ ABC = ∠ ade = 90 °, try to connect two line segments by taking the points marked with letters in the figure as the end points. If the two line segments you connect satisfy one of the equal, vertical or parallel relationships, please write it out and prove it
- 16. As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree
- 17. As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree
- 18. As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree
- 19. As shown in the figure, at the isosceles right angle △ ABC, ∠ C = 90 °, AC = BC, D is any point on AB, AE ⊥ CD is at e, BF ⊥ CD intersects the extension line of CD at F, CH ⊥ AB is at h, Give AE to g, verify: CE = BF
- 20. As shown in the figure, be and CF are the heights of △ ABC, M is the midpoint of BC, BC = 10, EF = 5, root 2, and find the area of triangle EFM kuaidiann