Diagonal $AC$ of a parallelogram $ABCD$ bisects $\angle A$ (see Fig). Show that it bisects $\angle C$ also.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) Given: $ABCD$ is a parallelogram in which diagonal $AC$ bisects $\angle A$. Thus,$\angle DAC = \angle BAC$.
To prove: $AC$ bisects $\angle C$,i.e.,$\angle DCA = \angle BCA$.
Proof:
$1$. Since $ABCD$ is a parallelogram,$AB \parallel DC$ and $AC$ is a transversal.
Therefore,$\angle BAC = \angle DCA$ (Alternate interior angles) ....... $(1)$
$2$. Also,$BC \parallel AD$ and $AC$ is a transversal.
Therefore,$\angle DAC = \angle BCA$ (Alternate interior angles) ....... $(2)$
$3$. Since $AC$ bisects $\angle A$,we have $\angle DAC = \angle BAC$ ....... $(3)$
$4$. From equations $(1)$,$(2)$,and $(3)$,we get:
$\angle DCA = \angle BCA$
Hence,$AC$ bisects $\angle C$.

Explore More

Similar Questions

In $\Delta ABC$ and $\Delta DEF$,$AB = DE$,$AB \parallel DE$,$BC = EF$ and $BC \parallel EF$. Vertices $A, B$ and $C$ are joined to vertices $D, E$ and $F$ respectively (see Fig). Show that quadrilateral $ACFD$ is a parallelogram.

$l, m$ and $n$ are three parallel lines intersected by transversals $p$ and $q$ such that $l, m$ and $n$ cut off equal intercepts $AB$ and $BC$ on $p$ (see Fig). Show that $l, m$ and $n$ cut off equal intercepts $DE$ and $EF$ on $q$ also.

$ABCD$ is a rhombus. Show that diagonal $AC$ bisects $\angle A$ as well as $\angle C$ and diagonal $BD$ bisects $\angle B$ as well as $\angle D$.

In parallelogram $ABCD$,two points $P$ and $Q$ are taken on diagonal $BD$ such that $DP = BQ$ (see Fig). Show that: $AQ = CP$.

$ABCD$ is a parallelogram in which $P$ and $Q$ are mid-points of opposite sides $AB$ and $CD$ respectively. If $AQ$ intersects $DP$ at $S$ and $BQ$ intersects $CP$ at $R$,show that: $APCQ$ is a parallelogram.

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