The area of the incircle of an equilateral triangle of side $42 \ cm$ is (in $cm^2$)

The perimeter of a square is $48\, cm$. The area of a rectangle is $4\, cm^2$ less than the area of the square. If the length of the rectangle is $14\, cm$,then its perimeter is.......$cm$.

Seven equal cubes each of side $5 \, cm$ are joined end to end. Find the surface area of the resulting cuboid? (in $cm^2$)

The diameter of a circular wheel is $7\, m$. How many revolutions will it make in travelling $22\, km$?

The difference of the areas of two squares drawn on two line segments of different lengths is $32 \, cm^2$. Find the length of the greater line segment if one is longer than the other by $2 \, cm$. (in $cm$)

In the given figure,there is a large semicircle with diameter $AB = 56 \ cm$. Inside this,there are four smaller identical semicircles with diameters $AE, EF, FG,$ and $GB$ along the diameter $AB$. $A$ circle is inscribed such that it is tangent to the large semicircle and the two middle smaller semicircles. What is the area (in $cm^2$) of the shaded region?