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RT, in triangle ABC, ab = AC = 10, point D on BC, de parallel AC, DF parallel AB, find the perimeter of quadrilateral AEDF
The perimeter is ab + AC = 20
Because AB = AC, so ∠ B = ∠ C, and because De is parallel to AC, DF is parallel to AB, then ∠ B = ∠ EDB, ∠ C = ∠ FDC, then EB = ed, FC = FD, the perimeter of quadrilateral is equal to AE + AF + de + DF = AE + be + AF + FC = AB + AC = 20
As shown in the figure, in △ ABC, ab = AC = 5, D is the point on the edge of BC, de ∥ AB intersects AC at point E, DF ∥ AC intersects AB at point F, then the perimeter of quad afde is______ ．
∵ AB = AC = 5, ∵ B = ∵ C, from DF ∥ AC, ∵ FDB = ∵ C = ∵ B, ∵ FD = FB, similarly, de = EC. ∵ perimeter of quadrilateral afde = AF + AE + FD + de = AF + FB + AE + EC = AB + AC = 5 + 5 = 10
As shown in the figure, in △ ABC, de ‖ BC, and s △ ade: s quadrilateral bced = 1:2, BC = 26. Find the length of de
∵ s △ ade: s quadrilateral bced = 1:2, s △ ABC = s △ ade + s quadrilateral DBCE, ∵ s △ ade: s △ ABC = 1:3, and ∵ de ‖ BC, ∵ ade ∵ ABC, ∵ s △ ade: s △ ABC = (DEBC) 2, and ∵ BC = 26, ∵ de = 22
As shown in the figure, in △ ABC, de ‖ BC, and s △ ade: s quadrilateral bced = 1:2, BC = 26. Find the length of de
∵ s △ ade: s quadrilateral bced = 1:2, s △ ABC = s △ ade + s quadrilateral DBCE, ∵ s △ ade: s △ ABC = 1:3, and ∵ de ‖ BC, ∵ ade ∵ ABC, ∵ s △ ade: s △ ABC = (DEBC) 2, and ∵ BC = 26, ∵ de = 22
As shown in the figure, in isosceles △ ABC, ab = AC, ∠ BAC = 100 °, extend AB to D, make ad = BC, connect DC, then the degree of ∠ BCD is______ ．
As shown in the figure, in isosceles △ ABC, ab = AC, ∠ BAC = 100 °, extend AB to D, make ad = BC, connect DC, then the degree of ∠ BCD is______ ．
Known: as shown in the figure, in △ ABC, ab = AC, ad bisects ∠ BAC, CE ⊥ AB in E, intersects ad in F, AF = 2CD, find the degree of ∠ ace
∵ AB = AC, ad bisection ∠ BAC, ∵ BD = DC, ad ⊥ BC, that is BC = 2CD, ∵ AF = 2CD, ∵ AF = BC, ∵ CE ⊥ AB, ad ⊥ BC, ∵ AEF = ∠ BEC = ∠ ADC = 90 °, ∵ AFE = ∠ DFC, ∵ AEF + ∠ AFE + ∠ EAF = 180 °, DFC + ∠ FDC + ∠ FCD = 180 °, and ∵ EAF = ∠ FCD, in △ AEF
In the triangle ABC, angle a = 70 degrees. If angle B intersects the bisector of angle c at point E, then angle BEC =?
If the bisector of angle B and angle c intersects at point E, then point E is a triangle ABC inscribed circle,
The angle BEC is the center angle
Angle BEC = 1 / 2 (angle ACB + angle ABC)
Because angle ACB + angle ABC + angle a = 180 degrees
So: angle BEC = 1 / 2 (angle ACB + angle ABC) = 1 / 2 (180 angle a) = 1 / 2 (180-70) = 55 degrees
Known triangle ABC, angle c is equal to 90 degrees, be is the angle bisector of angle B, intersection AC at F, find the degree of angle BEC, urgent!
The problem is serious. Let's hand it over to AC and E··
In △ ABC, if the diplomatic bisector of ∠ B and the outer bisector of ∠ C intersect at point E, then ∠ BEC is equal to ()
A 1/2（90°-∠A） B 90°-∠A C 1/2（180°-∠A） D 180°-∠A
The sum of the external angles of ∠ B ＋ C = 180 ° - a ∠ B ∠ C is 360 ° - (180 ° - a) = 180 °+ ∠ a ∠ EBC + ∠ ECB = (180 °+ ∠ a) △ 2 = 90 ° + 1 / 2 ∠ a ∠ BEC = 180 ° - (90 ° + 1 / 2 ∠ a) = 90 ° - 1 / 2 ∠ a = 1 / 2 (180 ° - a)
RELATED INFORMATIONS
- 1. As shown in the figure, in △ ABC, de ‖ BC, ad: DB = 3:2 (1) find the value of DEBC; (2) find the value of bced & nbsp; of s △ ADEs quadrilateral
- 2. As shown in the figure, in RT △ ABC, ∠ C = 90 °, AC = 4cm, BC = 3cm, now fold △ ABC to make vertex A and B coincide, then the length of crease De is () cm A. 52B. 154C. 158D. 5
- 3. Triangle ABC, AC = BC, angle c = 90 degree, point D on BC, fold triangle ACD along ad, point C just falls on point E on AB, if AB = 6cm Finding the perimeter of triangle deb The picture can't be sent out
- 4. Original proposition: √ a ＞ B, then a ＞ B (write its inverse proposition, no proposition, inverse no proposition)
- 5. If a = B, then a = B (fill in "true" or "false") proposition, its inverse proposition is, it is (fill in "true" or "false") proposition
- 6. If three line segments a, B and C satisfy a square = C square - b square, is the triangle formed by these three line segments a right triangle? Why? Please explain the process and reasons,
- 7. Let a and B be the lengths of two right angles of a right triangle and (A2 + B2) (3 under the root of A2 + b2-4) = - 12, then the value of A2 + B2 is Thank you for your correct answer!
- 8. Write down the inverse proposition of the following proposition, and judge whether it is true or false. 1. The same position angle is equal, and the two lines are parallel. 2. The inner stagger angle is equal, and the two lines are parallel
- 9. The converse proposition of the proposition "equal angle, parallel two lines" is as follows:______ ．
- 10. If △ ABC ≌ △ DEF is known, if △ ABC and perimeter are 38, ab = 14, AC = 8, try to find the length of EF respectively 5 yuan fortune reward
- 11. It is known that: as shown in the figure, point D is a point on the edge AC of △ ABC, passing point D makes de ⊥ AB, DF ⊥ BC, e and F are perpendicular feet, then passing point D makes DG ∥ AB, intersecting BC at point G, and de = DF. (1) prove: DG = BG; (2) prove: BD bisects EF vertically
- 12. As shown in the figure, in △ ABC, ∠ B = 90 °, ab = 3, AC = 5, fold △ ABC so that point C coincides with point a, and the crease is De, then the perimeter of △ Abe is______ ．
- 13. In triangle ABC, AF: FB = BD: DC = Ce: AE = 3:2, be, CF and ad intersect point igh on BC, AC and ab respectively, and the area of IgH is 1
- 14. In the triangle ABC, BD.CD They are the diplomatic bisector of angle ABC and angle ACB
- 15. As shown in the figure, in △ ABC, BD and CD divide ∠ ABC and ∠ ACB equally, and try to explain ∠ d = 90 ° + & # 189; ∠ a
- 16. As shown in the figure, BD is the extension of the intersection of the middle line AE ⊥ BD on the edge AC of △ ABC at the point ECF ⊥ BD. be + BF. = 2bd is proved at the point F It's sloppy
- 17. In ABC, BD is the inner bisector of angle B, CE is the outer bisector of angle c, AF is perpendicular to BD, Ag is perpendicular to CE, FG and ABC?
- 18. (1 / 3) the known triangles ABC, (|) BD and CE are bisectors of angle B and angle c, respectively. Through point a, make AF vertical BD, Ag vertical CE, the perpendicular feet are f, G, connecting FG (1 / 3) the known triangles ABC, (|) BD and CE are bisectors of angle B and angle c, respectively. Through point a, make AF vertical BD, Ag vertical CE, and the perpendicular feet are f, G, connecting FG. (2) if C
- 19. It is known that in △ ABC, points D, e and F are points on BC, AB and AC respectively, AF is parallel to ED, and AF = ed, extend FD to point G, so that DG = FD, and verify that ED and Ag are equally divided,
- 20. In △ ABC, ∠ C = 90 ° and the intersection line BC of AB is at D. if ∠ bad - ∠ DAC = 22.5 °, then the degree of ∠ B is______ ．