In $\Delta ABC$,$\overline{AD}$ is a median. The bisectors of $\angle ADB$ and $\angle ADC$ intersect $\overline{AB}$ and $\overline{AC}$ at $E$ and $F$ respectively. Prove that $\overline{EF} \parallel \overline{BC}$.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) In $\Delta ABD$,$DE$ is the bisector of $\angle ADB$. By the Angle Bisector Theorem,$\frac{AE}{EB} = \frac{AD}{DB}$.
Since $\overline{AD}$ is a median,$D$ is the midpoint of $\overline{BC}$,so $DB = DC$. Thus,$\frac{AE}{EB} = \frac{AD}{DC}$.
In $\Delta ADC$,$DF$ is the bisector of $\angle ADC$. By the Angle Bisector Theorem,$\frac{AF}{FC} = \frac{AD}{DC}$.
Comparing the two equations,we get $\frac{AE}{EB} = \frac{AF}{FC}$.
By the Converse of the Basic Proportionality Theorem (Thales Theorem) in $\Delta ABC$,since $\frac{AE}{EB} = \frac{AF}{FC}$,it follows that $\overline{EF} \parallel \overline{BC}$.

Explore More

Similar Questions

The two triangles in the figure are congruent using a congruence theorem. It is given that $OQ = OR$. Which of these conditions,along with the given condition,is sufficient to prove that the two triangles are congruent to each other?

The diagonals of $\square XYZW$ intersect at right angles. Prove that $XY^{2} + ZW^{2} = YZ^{2} + XW^{2}$.

In a quadrilateral $ABCD$,$\angle A + \angle D = 90^{\circ}$. Prove that $AC^{2} + BD^{2} = AD^{2} + BC^{2}$.

Difficult
View Solution

In $\Delta ABC$,the bisector of $\angle A$ intersects $\overline{BC}$ at $D$. Prove that $BD = \frac{BC \times AB}{AB + AC}$ and $DC = \frac{BC \times AC}{AB + AC}$.

Difficult
View Solution

In $\Delta ABC$,$m \angle B = 90^{\circ}$ and $\overline{BD}$ is an altitude to the hypotenuse $AC$. If $AD = 9$ and $CD = 4$,find $BD$.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo