Question

the area of a square painting is 81 cm². what is the length of one side? options: -9, 40.5, 9, -40.5

Explanation:

Step1: Recall the formula for the area of a square

The area \( A \) of a square with side length \( s \) is given by the formula \( A = s^2 \).

Step2: Substitute the given area into the formula

We know that the area \( A = 81 \, \text{cm}^2 \). So we have the equation \( s^2 = 81 \).

Step3: Solve for \( s \)

To find \( s \), we take the square root of both sides of the equation. Since the length of a side cannot be negative (it represents a physical length), we consider the positive square root. So \( s=\sqrt{81} = 9 \).

Answer:

The length of one side is \( 9 \, \text{cm} \), so the correct option is the one with 9 (the orange option with 9).