Draw all the possible lines of symmetry of letter H.

Draw the lines of symmetry for an equilateral triangle.

In the figure above, $ABCD$ is a parallelogram, and if $AC=30 \mathrm{cm} \mathrm{and} BD=20 \mathrm{cm}$, $CP+DP=k \mathrm{cm}$, find $k$.

In an $n-$sided regular polygon, each exterior angle is $72°$. Find $k,$ if the sum of all the interior angles of the polygon is $k°$.

In the given figure, $AB=AC \mathrm{and} BC$ is extended to the point $D$.  If $y-x=k°$, find $k$.

In the given figure, $AB=BC=8 \mathrm{cm} \mathrm{and} AD=CD=10 \mathrm{cm}$, which axiom best proves the congruence of $△ABD \mathrm{and} △CBD$?

In the given figure, $BA$ is parallel to $DC$ and $PQ$ is a transversal of $BA \mathrm{and} DC$. $\angle PMA=70° \mathrm{and} \angle DNM=2x+30°$, then find $k$, if the value of $x=k°$.

In the given figure, $AD=AC=BD$. The points $B, D \mathrm{and} C$ are collinear. If $\angle CAD=80°$ and $\angle DAB=k°$, find $k$.

In the given figure, $ACB$ is a straight line and $\angle ACD:\angle DCB=2:1$. If $\angle DCB=k°$, find $k$.