Polygons

Give the area of the isosceles trapezium $ABCD$, if $AB\parallel CD$, $|CD|=4\mathrm{cm}$, the height $v=16\mathrm{cm}$ and the measure of $\measuredangle CAB$ is ${30}^{\circ }$. Round the result to units.

The vertical cross-section of the embankment around the pond has the shape of an isosceles trapezium. Calculate the angle of inclination of the embankment if the embankment is $2\mathrm{m}$ high, the top width is $3\mathrm{m}$ and the arms are $4\mathrm{m}$ long.

A side of a rhombus is $35\mathrm{cm}$ long and the length of one of its diagonals is $56\mathrm{cm}$. Give the measure of the angle that the other diagonal makes with the side of the rhombus. Round the result to two decimal places.

Given the rhombus $ABCD$ with the diagonal $|DB|=8\mathrm{cm}$. The measure of $\measuredangle DAB$ is ${60}^{\circ }$. Calculate the circumference of the rhombus.