Question

A paper is in the form of a rectangle ABCD in which $AB=18cm$ and $BC=14cm.$ A semi-circular portion with $BC$ as diameter is cut off. Find the area of the remaining paper.

Answer 1

$\therefore$ $Areaofrectangular$ $ABCD=l\times b$
$=AB\times BC$
$=18\times 14=252c{m}^2$
$Radiusofsemicircle$ $\left(r\right)$
$=\frac{1}{2}BC=\frac{1}{2}\times 14=7cm$
$\therefore$ $Areaofsemicircle$
$=\frac{1}{2}\pi r^2=\frac{1}{2}\times \frac{22}{7}\times (7{)}^2$
$=77c{m}^2$
$Areaoftheremainingportion=Areaofrectangle-AreaofofSemicircle$
$=252-77$
$=175c{m}^2$