Find the area of the following:
a. A square of side 21 cm
b. A rectangle measuring 23 cm by 12 cm

Answer

To solve the problem of finding the area of a square and a rectangle, we will follow these steps:

### Step 1: Calculate the area of the square
The formula for the area of a square is:
\[ \text{Area} = \text{side} \times \text{side} \]
Given that the side of the square is 21 cm, we can substitute this value into the formula:
\[ \text{Area} = 21 \, \text{cm} \times 21 \, \text{cm} \]
Calculating this gives:
\[ \text{Area} = 441 \, \text{cm}^2 \]

### Step 2: Calculate the area of the rectangle
The formula for the area of a rectangle is:
\[ \text{Area} = \text{length} \times \text{breadth} \]
Given that the length of the rectangle is 23 cm and the breadth is 12 cm, we can substitute these values into the formula:
\[ \text{Area} = 23 \, \text{cm} \times 12 \, \text{cm} \]
Calculating this gives:
\[ \text{Area} = 276 \, \text{cm}^2 \]

### Final Answer
- The area of the square is \(441 \, \text{cm}^2\).
- The area of the rectangle is \(276 \, \text{cm}^2\).

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