As shown in the figure, △ ABC, D is the midpoint of BC, e and F are two points on the edge of AB and AC respectively, ed ⊥ FD, which proves that be + CF > EF
It is proved that: extend FD to point m, make MD = FD, connect BM, EM, ∵ D as the midpoint of BC, ∵ BD = CD, in △ FDC and △ MDB, FD = DM, ≌ FDC ≌ mdbcd = BD, ≌ FDC ≌ MDB (SAS), ≌ BM = CF, and ∵ FD = DM, ed ⊥ MF, ≁ ED is the vertical line of MF ≁ EF = em, in △ EBM, be + BM >
RELATED INFORMATIONS
- 1. As shown in the figure, in △ ABC, BD bisects ∠ ABC, de ‖ BC intersects AB at point E, EF ‖ AC intersects BC at point F. try to guess the size relationship between be and CF, and explain the reasons, as shown in figure.doc
- 2. In △ ABC, ab = AC, D is a point on BC, de ⊥ AB and E, DF ⊥ BC, intersection AC and F, ∠ AFD = 160 °, find the degree of ∠ A and ∠ EDF RT
- 3. It is known that in the triangle ABC, the angle a is equal to 50 ° and DEF is the point on BC AB AC, DB= de.dc=df , find the angle EDF
- 4. In the triangle ABC, ab = AC, point D is on AC, and BD = BC = ad, De is the middle line of the triangle abd, and DF = BF, find the degree of ∠ EDF
- 5. As shown in the figure, in △ ABC, ab = AC, EB = BD = DC = CF, ∠ a = 40 °, then the degree of ∠ EDF is______ Degree
- 6. As shown in the figure: in △ ABC, D is the point on BC, de ⊥ Ba is in E, DF ⊥ AC is in F, and de = DF? And explain the reason
- 7. As shown in the figure: in △ ABC, D is the point on BC, de ⊥ Ba is in E, DF ⊥ AC is in F, and de = DF? And explain the reason
- 8. It is known that in the triangle ABC, D is a point of BC, De is perpendicular to AB and DF is perpendicular to AC and F, and De is equal to DF. What is the relationship between AD and ef D is a point on BC. I have the wrong number
- 9. As shown in the figure, circle O is the circumscribed circle of triangle ABC
- 10. The three sides of a right triangle are 6 cm, 8 cm and 10 cm long respectively. What shape can be obtained by rotating the two right sides for one circle? What's the maximum volume of it?
- 11. It is known that: as shown in the figure, in △ ABC, ∠ B = ∠ C, points D, e and F are points on edges BC, AB and AC respectively, be = CD, connecting de and DF, with ∠ EDF = ∠ C, then are de and DF equal? Try to explain the reason
- 12. It is known that: as shown in the figure, in △ ABC, ∠ B = ∠ C, points D, e and F are points on edges BC, AB and AC respectively, be = CD, connecting de and DF, with ∠ EDF = ∠ C, then are de and DF equal? Try to explain the reason
- 13. In the triangle ABC, ab = AC, points D, e and F are on the sides of AB, BC and AC respectively. De = DF and EDF = angle a are known. Find out the similar triangles in the graph and prove them
- 14. In △ ABC, ab = AC, points D, e and F are on the sides of AB, BC and AC respectively, de = DF,
- 15. As shown in the figure, ab = De, AC ∥ DF, BC ∥ EF
- 16. In RT △ ABC, ∠ C = 90 °, a right triangle is solved by the following conditions (1) If we know that a = 4 times radical 3, B = 2 times radical 3, then C =? (2) If a = 10, C = 10 times the root 2, then ∠ B =? (3) If C = 20 and a = 60 ° are known, then a =? (4) If B = 35 and a = 45 ° are known, then a =?
- 17. In RT △ ABC, a = 30.01, ∠ B = 80 ° 24 'and ∠ C = 90 °, right triangle can be solved according to the following conditions
- 18. The side length of equilateral △ ABC is a, and the area of inscribed square defg of its inscribed circle is obtained
- 19. The square defg is the inscribed square of △ ABC, D is on ab. G is on AC, e and F are on BC, am ⊥ BC is on M, intersecting DG is on H. if ah is 4 and the side length of the square is 6, the length of BC is calculated
- 20. As shown in the figure, the area of triangle ABC is 120 square centimeters, D is the midpoint of BC & nbsp;, AE = 13be, EF = 12fd, then the area of triangle AFD is______ Square centimeter