Question
In the figure $\text{ABCD}$ is a parallelogram, $\text{CE}$ bisects $\angle\text{C}$ and $\text{AF}$ bisects $\angle\text{A}$. In each of the following, if the statement is true, give a reason for the same.
$i. \angle\text{A}=\angle\text{C}$
$ii. \angle\text{FAB}=\frac{1}{2}\angle\text{A}$
$iii.\angle\text{DCE}=\frac{1}{2}\angle\text{C}$
$iv. \angle\text{CEB}=\angle\text{FAB}$
$v. \text{CE}\parallel\text{AF}$

Answer


In parallelogram $\text{ABCD}$
$\text{CE}$ is the bisector of $\angle\text{C}$ and and $\text{AF}$ is the bisector of $\angle\text{A}$.
$i. \angle\text{A}=\angle\text{C} ($Opposite angles of a parallelogram$)$
$ii. AF$ is the bisector of $\angle\text{A}$
$\angle\text{FAB}=\frac{1}{2}\angle\text{A}$
$iii. CE$ is the bisector of $\angle\text{C}$
$\angle\text{DCE}=\frac{1}{2}\angle\text{C}$
$iv.$From $(i)$, $(ii)$ and $(iii)$
$\angle\text{FAB}=\angle\text{DCE}$
$v. \angle\text{FAB}=\angle\text{DCE}$
But these are opposite angles of quadrilateral $\text{AECF}$
$\text{AB}$ or $\ce{AE \| DC}$ or $\text{FC}$
$\text{AECF}$ is a parallelogram
$\ce{CE \|AF}$
Hence proved.

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