Q: 1 Parallelogram ABCD and rectangle ABEF are on the same base AB and have equal areas. Show that the perimeter of the parallelogram is greater than that of the rectangle.
We have $\| g m \mathrm{ABCD}$ and a rectangle $A B E F$ both lie on the same base $A B$ such that, $\boldsymbol{a r}(\| g m \mathrm{ABCD})=\boldsymbol{a r}(\mathrm{ABEF})$ for rectangle, $\mathrm{ABEF}$
and for $\| g m, \mathrm{ABCD}$
$\Rightarrow C D=E F$
$\Rightarrow A B+C D=A B+E F$
Since $\triangle B E C$ and $\triangle A F D$ are right-angled triangles
Therefore, $A D>A F$ and $B C>B E$
$\Rightarrow(B C+A D)>(A F+B E)$
Adding equation (i) and (ii), we get
$(A B+C D)+(B C+A D)>(A B+B E)+(A F+B E)$
$Rightarrow(A B+B C+C D+D A)>(A B+B E+E F+F A)$
Hence proved, that the perimeter of ||gm $ABCD$ is greater than the perimeter of the rectangle $ABEF$.