What is the area of the shaded portion if each side of the square measures $21\,cm$? (in $cm^2$)

The length of a rectangle is increased by $33.33 \%$. By what percent should the width be decreased to maintain the same area? (in $\%$)

The area of a square field is $6050\, m^2$. How much time will it take to reach from one of its corners to the opposite corner at the rate of $10\, m$ in every $30$ seconds?

The length of a rectangular plot is $20 \ m$ more than its breadth. If the cost of fencing the plot at $₹ 26.50/m$ is $₹ 5300$,what is the length of the plot in metres?

The perimeter of a right-angled triangle is $90\, cm$ and its hypotenuse is $39\, cm$. Find its other sides.

The radius of the wheel of a vehicle is $70\, cm$. The wheel makes $10$ revolutions in $5\, seconds$. The speed of the vehicle is......$km/h$.