ta có:
\(\frac{BD}{DC}=\frac{AB}{AC}=\frac{3}{7}\)( do AD là tia phân giác của \(\widehat{BAC}\))
\(\Rightarrow\frac{BD}{BC}=\frac{3}{11}\)
Ta có:
\(\frac{ED}{AC}=\frac{BD}{BC}=\frac{3}{11}\Rightarrow ED=\frac{3AC}{11}=\frac{3.7}{11}=\frac{21}{11}\)
Let ABC be a triangle with AB = 3cm, AC = 7cm. The internal bisector of the angle BAC intersects BC at D. The line passing through D and parallel to AC cuts AB at E. Find the measure of DE. Answer: DE = ..........cm.
with triangle ABC, d is the line passing through B, E of AC. Via E draw straight lines parallel to AB and BC cut d at M, N. D is the intersection of ME and BC. NE lines cut AB and MC at F and K. CMR AFN triangles are in the same form as the MDC triangle
Let P be the intersection point of 3 internal bisectrices of a given triangle ABC. The line passing through P and perpendicular to CP intersects AC and BC at M and N. If AP=3cm, BP=4cm, compute AM/BN?
Let ABC be an isoceles triangle (AB = AC) and its area is 501cm2. BD is the internal bisector of the angle ABC (D ∈ AC), E is a point on the opposite ray of CA such that CE = CB. I is a point on BC such that CI = 1/2 BI. The line EI meets AB at K, BD meets KC at H. Find the area of the triangle AHC.
Giúp mình với! Mình sắp thi rồi.
In triangle ABC, BC=AC and BCA=900. D and E are points on AC and AB respectively such that AD=AE and 2CD =BE.Let P be the point of intersection of BD with the bisector of angle CAB. What is the angle PCB in degrees?
1. Two bisector BD and CE of the triangle ABC intersect at O. Suppose that BD.CE = 2BO.OC . Denote by H the point in BC such that .\(OH⊥BC\) . Prove that AB.AC = 2HB.HC
2. Given a trapezoid ABCD with the based edges BC=3cm , DA=6cm ( AD//BC ). Then the length of the line EF ( \(E\in AB,F\in CD\) and EF // AD ) through the intersection point M of AC and BD is ............... ?
3. Let ABC be an equilateral triangle and a point M inside the triangle such that \(MA^2=MB^2+MC^2\) . Draw an equilateral triangle ACD where \(D\ne B\) . Let the point N inside \(\Delta ACD\) such that AMN is an equilateral triangle. Determine \(\widehat{BMC}\) ?
4. Given an isosceles triangle ABC at A. Draw ray Cx being perpendicular to CA, BE perpendicular to Cx \(\left(E\in Cx\right)\) . Let M be the midpoint of BE, and D be the intersection point of AM and Cx. Prove that \(BD⊥BC\)
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Given the right triangle ABC (A^ = 90o), BD is the bisector of the angle at B ( D of AC ). If AD = 6cm and AB = 12cm then the area of the right triangle ABC is ...... cm2.
Given the right triangle ABC (A^ = 90o), BD is the bisector of the angle at B ( D of AC ). If AD = 6cm and AB = 12cm then the area of the right triangle ABC is ...... cm2.
