How many bricks,each measuring $25\, cm \times 15\, cm \times 8\, cm$,will be required to build a wall $10\, m \times 4\, dm \times 5\, m$ if $\frac{1}{10}$ of its volume is occupied by mortar?

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?

Find the perimeter (in $cm$) of a semicircle of radius $28\, cm$.

$ABCD$ is a cyclic quadrilateral. $AB$ and $DC$ when produced meet at $P$. If $PA = 8 \ cm$,$PB = 6 \ cm$,and $PC = 4 \ cm$,then the length (in $cm$) of $PD$ is:

The circumference of a circle whose area is $24.64\, m^{2}$ is ....... $m$.

$A$ square is inscribed in a circle whose radius is $4\, cm$. The area of the portion between the circle and the square is