Mwangi is painting the wall of his square shop. One side of the wall is 4.5 meters long. The cost of paint is Ksh. 200 per square metre. Calculate the total area of the wall and determine how much it will cost him to buy enough paint for it.

The petri dish is square, and its area is $0.64 \text{ cm}^{2}$.

The area $A$ of a square with side length $s$ is given by the formula:

To find the side length, we take the square root of the area:

The length of the dish is $\boxed{0.8 \text{ cm}}$.

3 zimekamilika, zimebaki 2 leo. Unapiga hatua.