correct answer is: c) 21%

Explanation

Here, the square field 1 side length is 100 m
We know,
Area of a square field = (side × side)
\therefore Area of the square field is =\left(100\times100\right) sq.m
\rightarrow\ 10000 sq.m
Now, if a 5 m wide path is laid around the square field, then the new square field’s side length is =\{100+\left(5+5\right)\} m _{[increase both side]}
\rightarrow110 m
\therefore New area of the square field with the path is =\left(110\times110\right) sq.m
\rightarrow12100 sq.m
\therefore Difference between new and old area is =\left(12100-10000\right) sq.m
\rightarrow2100 sq.m
\therefore Percentage increase =\large\left(\frac{2100}{10000}\normalsize\times100\right)\normalsize\% [base 10000]
\rightarrow21\%
Ans: Percentage increase in the square field is 21%.

Another method to articulate this particular query is available:
1. Determine the percentage increase in the total area of a square field with side length 100m when a 5m wide path is constructed around it.
2. What is the percentage growth in the area of a square field of 100m side length when a 5m wide path is introduced around it?
3. Calculate the percentage increase in the square field’s area when a 5m wide path is added around it, given that its side length is 100m.
4. Calculate the percentage increase in the area of a square field with a side length of 100m when a 5m wide path is laid around it.
5.Find out the percentage change in the area of a square field measuring 100m on each side after a 5m wide path is added around it.