The figure below shown rectangle ABCD and 3 shaded triangles. The total area of the shaded parts is 300cm$^2$. Given that AB // EF// DC and BC is 10cm, FindAB.

A piece of wire, forming 2 identical semi-circle as shown in figure 1, was straightened and bent into a square as shown in Figure2. Find the area of the square, giving your answer to 2 decimal places. $(Take \pi = 3.14)$

The figure below, not drawn to scale, is made up of a square ABCD and two triangle EFG and FKH, overlapping one another. The square has an area of 81cm$^2$. FK is 14cm and it is $\frac{2}{3}$ of the length of FG. Find the area of the figure.

The rectangle below is divided into four prats W, X, Y and Z. The ratio of area W to area X is 3 : 5. The ratio of area Y to area Z is 1: 2. What fraction of the total area is area W?