Question

The area of the square is \[81c{m^2}\]. Find the perimeter of a square

Answer 1

Hint: Here the question is related to mensuration. The area of a square is given in the question, by using the formula of the area first we determine the value of the length of a square and then by using the formula of perimeter of a square is calculated. Hence that we will be required solution for the given question.

Complete step-by-step answer:
The square is a plane figure. In a square all sides are equal.
On considering the given question.
The area of a square is given as \[81c{m^2}\]
The formula for the area of a square is given by \[A = {s^2}\], here we have the value for the area and we have to determine the value of length of a square.
On substituting the known values for the formula we have
\[ \Rightarrow 81 = {s^2}\]
On taking square root on both sides we get
\[ \Rightarrow s = 9\]
We are considering the positive value because the length value can’t be a negative term.
Therefore the length of a square is \[9\,cm\]
Now we have to determine the perimeter of a square.
 The formula for the perimeter of a square is given by \[P = 4 \times s\]
On substituting the value of the length of a square in above formula we have
\[ \Rightarrow P = 4 \times 9\]
On multiplying we get
\[ \Rightarrow P = 36\,cm\]
Therefore the perimeter of a square is \[36\,cm\]
So, the correct answer is “36 cm”.

Note: To solve these kinds of problems we have to know about the formulas. In a measurement we have to remember to write a unit. For the perimeter the unit will be the same as the unit of the given length and for the area the unit will be square units. Students must remember the units and they have to mention it.