Is the area of the circle inscribed in a square of side $a \,cm , \pi a^{2}\, cm ^{2}?$ Give reasons for your answer.
False
Let $ABCD$ be a square of side $a.$
$\therefore$ Diameter of circle $=$ Side of square $= a$
$\therefore \quad$ Radius of circle $=\frac{a}{2}$
$\therefore \quad$ Area of circle $=\pi$ (Radius) $^{2}=\pi\left(\frac{a}{2}\right)^{2}=\frac{\pi a^{2}}{4}$
Hence, area of the circle is $\frac{\pi a^{2}}{4} \,cm ^{2}$
If the sum of the circumferences of two circles with radii $R_{1}$ and $R_{2}$ is equal to the circumference of a circle of radius $R ,$ then
The length of the minute hand of a clock is $10.5\, cm .$ Find the area of the region swept by it between $2.25 \,PM$ and $2.40 \,PM$. (in $cm^2$)
Sides of a triangular field are $15\, m , 16 \,m$ and $17\, m$. With the three corners of the field a cow, a buffalo and a horse are tied separately with ropes of length $7 \,m$ each to graze in the field. Find the area of the field which cannot be grazed by the three animals.
Two minor sectors of two distinct circles have the measure of the angle at the centre equal. If the ratio of their areas is $4: 9,$ then ratio of the radii of the circles is ........
In a circle, the area of a sector formed by two radii perpendicular to each other is $38.5 \,cm ^{2}$. Find the radius of the circle. (in $cm$)