An error $2\%$ in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is:

A rectangular park $60 \mathrm{m}$ long and $40 \mathrm{m}$ wide has two concrete crossroads running in the middle of the park and rest of the park has been used as a lawn, If the area of the lawn is $2109$ sq. $m$, then what is the width of the road.

A man walked diagonally across a square lot. Approximately, what was the percent saved by not walking along the edges?

The diagonal of a rectangle is $\sqrt{41}cm$ and its area is $20 sq. cm$. The perimeter of the rectangle must be: