The height of an equilateral triangle of side $\text{'}a\text{'}$ is given by

The area of a trapezium is $34\mathrm{ }\mathrm{c}{\mathrm{m}}^2$ and the length of one of the parallel sides is 10 cm and its height is 4 cm. Find the length of the other parallel side.

Length of the face of a trapezium shaped field ABCD is 120 m. If BC = 48 m, CD = 17 m and AD = 40 m, Find the area of this field. Side AB is perpendicular to the parallel sides AD and BC.

Mohan wants to buy a trapezium shaped field. Its side along the river is parallel to and twice the side along the road. If the area of this field is $10500\mathrm{ }{\mathrm{m}}^2$ and the perpendicular distance between the two parallel sides is 100 m, Find the length of the side along the river.

A car has two wipers which do not overlap. Each wiper has a blade of 25 cm sweeping through an angle of ${115}^o$ . Find the total area cleaned by each sweep of blades.