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 \(BD⊥BC\)
Lesson 1: Trapezoid sheet has a large bottom 2.8dm, baby bottom 1.6dm, height 0.8dm.
a) Calculate the area of the cardboard?
b) Cut a quarter of the area. Calculate the area of the cardboard remaining?
Lesson 2: ABCD rectangle with DC length = 27cm, AD = 20.4cm. E is a point on AB. Calculate the area of the triangle ECD?
Lesson 3: (HSKG): A trapezoidal field with a baby bottom 26m, the bottom is 8m lower than baby, the bottom is 6m lower. Average 100m2 harvested 70.5 kg paddy. How much is the field harvested?
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?
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?
Given the Triangle ABC and the point M inside the triangle (M don't belong on any sides of triangle).let I be the intersection point of the line BM and the side AC
a, compare MA to MI+MB,then prove that MA +MB<IB+IA
b, compare IB to IC+CB, then prove that IB+IA<CA+CB
c, Demonstrate the inequality MA+MB<CA+CB
Given the Triangle ABC and the point M inside the triangle (M don't belong on any sides of triangle).let I be the intersection point of the line BM and the side AC
a, compare MA to MI+MB,then prove that MA +MB<IB+IA
b, compare IB to IC+CB, then prove that IB+IA<CA+CB
c, Demonstrate the inequality MA+MB<CA+CB
Môn j mà hay zâỵ sao dịch dc lên gogle dịch à
Given a square with the length of one side is 8 cm and a isosceles triangle with the length of its base is 12 cm. If the area of the square is equal to the area of the isosceles triangle then what is the length of the height of the isosceles triangle, in cm?
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?
Ta có
\(\widehat{ABM}=\widehat{APC}-\widehat{MPC}=\left(90+\frac{\widehat{ABC}}{2}\right)-90=\widehat{PBC}\)
Tương tự tra có: \(\widehat{NPB}=\widehat{PAM}\)
\(\Rightarrow\Delta MAP\approx\Delta NPB\)
\(\Rightarrow\frac{AP}{PB}=\frac{MA}{NP}=\frac{MP}{NB}\)
\(\Rightarrow MA.NB=NP.MP=NP^2=MP^2\)(Dễ thấy tam giác MNC cân có CP là đường cao và đường phân giác)
Ta lại có: \(\frac{MA}{NB}=\frac{MA^2}{MA.NB}=\frac{MA^2}{NP^2}=\frac{AP^2}{PB^2}=\frac{3^2}{4^2}=\frac{9}{16}\)
Given acute triangle ABC(AB<AC). O is the midpoint of BC, BM and CN are the altitudes of triangle ABC. The bisectors of angle \(\widehat{BAC}\)and \(\widehat{MON}\)meet each other at D. AD intesects BC at E. Prove that quadrilateral BNDE is inscribed in a circle.s
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