$ \mathrm{ABCD} $ is a parallelogram and $ \mathrm{AP} $ and $ \mathrm{CQ} $ are perpendiculars from vertices $ \mathrm{A} $ and $ \mathrm{C} $ on diagonal $ \mathrm{BD} $ (see below figure). Show that (i) $ \triangle \mathrm{APB} \cong \triangle \mathrm{CQD} $ (ii) $ \mathrm{AP}=\mathrm{CQ} $ "
Given :
$ABCD$ is a parallelogram and $AP$ and $CQ$ are perpendiculars from vertices $A$ and $C$ on diagonal $BD$.
To do :
We have to show that
(i) $\triangle {APB} \cong \triangle {CQD}$. (ii) $AP = CQ$.
Solution:
(i) In $\triangle ABP$ and $\triangle CDQ$,
$AB = CD$ [Opposite sides of parallelogram are equal]
$\angle APB = \angle CQD$ [Both are $90^o$ as given]
$\angle ABP = \angle CDQ$ [Alternate interior angles]
Therefore, $\triangle ABP \cong \triangle CDQ$.
(ii) $\triangle ABP \cong \triangle CDQ$.
So, all the angles and sides of both triangles are equal.
Therefore, $AP = CQ$.
Hence proved.
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