Question

PQRS is a parallelogram If PQ 12cm, QR 8 cm and AR 9 cm, find the area of ​​parallelogram ABCDand the length of RB.

Answer 1

The Area of parallelogram $PQRS$ is $108\ cm^{2}$ and the length of $RB$ is $13.5\ cm$

Step-by-step explanation:

Given,

$PQRS$ is a parallelogram, where $PQ=12\ cm,QR=8\ cm\ and\ AR=9\ cm$

∴ $PQ=RS=12\ cm$ and $QR=SP=8\ cm$ as shown in the figure.

If $PQ$ as a base.

Then Area of parallelogram $PQRS=(b\times h)$ where $b=Base$ and $h=AR=Height$

                                                               $=(12\times 9)$

                                                               $=108\ cm^{2}$

If we take $SP$ as base.

Then Area of  parallelogram $PQRS=(8\times RB)$

∴ $(8\times RB)=108$

⇒$RB=\frac{108}{8}$

∴ $RB=13.5\ cm$

So, The Area of parallelogram $PQRS$ is $108\ cm^{2}$ and the length of $RB$ is $13.5\ cm$