In $Fig.$,line segment $DF$ intersects the side $AC$ of a triangle $ABC$ at the point $E$ such that $E$ is the mid-point of $CA$ and $\angle AEF = \angle AFE$. Prove that
$\frac{BD}{CD} = \frac{BF}{CE}$

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) Given: In $\triangle ABC$,$E$ is the mid-point of $CA$ and $\angle AEF = \angle AFE$.
To prove: $\frac{BD}{CD} = \frac{BF}{CE}$.
Construction: Draw a line $CG$ parallel to $EF$ such that $G$ lies on $AB$.
Proof: Since $E$ is the mid-point of $CA$,we have $CE = AE$ $(i)$.
In $\triangle ACG$,since $CG \parallel EF$ and $E$ is the mid-point of $CA$,by the converse of the Mid-point Theorem,$F$ is the mid-point of $AG$. Thus,$GF = AF$ $(ii)$.
Also,in $\triangle ACG$,since $CG \parallel EF$,by the Mid-point Theorem,$EF = \frac{1}{2} CG$. However,this is not needed here. Instead,consider $\triangle BDF$ and $\triangle BCG$. Since $CG \parallel EF$,by the Basic Proportionality Theorem in $\triangle BDF$,we have $\frac{BD}{CD} = \frac{BF}{GF}$.
Since $\angle AEF = \angle AFE$,in $\triangle AEF$,we have $AE = AF$. From $(i)$ and $(ii)$,$CE = AE = AF = GF$. Therefore,$CE = GF$.
Substituting $GF = CE$ in the ratio $\frac{BD}{CD} = \frac{BF}{GF}$,we get $\frac{BD}{CD} = \frac{BF}{CE}$.
Hence proved.

Explore More

Similar Questions

In rhombus $PQRS$,$PR = 9$ and $QS = 12$. Find the perimeter of rhombus $PQRS$.

It is given that $\triangle ABC \sim \triangle PQR,$ with $\frac{BC}{QR} = \frac{1}{3}.$ Then,$\frac{\operatorname{ar}(\triangle PRQ)}{\operatorname{ar}(\triangle BCA)}$ is equal to

The perimeter of rhombus $ABCD$ is $116$. If $AC = 42$, find $BD$.

In $\Delta ABC$,$m \angle B = 90^{\circ}$ and $AC = 14\sqrt{2}$. If $AB = BC$,find the area of $\Delta ABC$.

In $\Delta ABC$,$m\angle B = 90^{\circ}$ and $\overline{BM}$ is an altitude. If $AC = 13$ and $CM = 9$,then $BM = \ldots \ldots$

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