Calculate the total area of three rectangular plots A, B, and C, given their dimensions and relationships in a diagram.

From the diagram:

• The length of Plot A is $40 \text{ m}$.
• The total width of the farm is $50 \text{ m}$ (indicated by the arrow at the bottom). Plot A spans this entire width.

$$\text{Area}_A = \text{length} \times \text{width} = 40 \text{ m} \times 50 \text{ m} = 2000 \text{ m}^2$$

From the diagram:

• The length of Plot B is $30 \text{ m}$.
• The total width of the bottom section (Plots B and C combined) is $50 \text{ m}$.
• The width of Plot C is $20 \text{ m}$.
• Therefore, the width of Plot B is $50 \text{ m} - 20 \text{ m} = 30 \text{ m}$.

$$\text{Area}_B = \text{length} \times \text{width} = 30 \text{ m} \times 30 \text{ m} = 900 \text{ m}^2$$

From the diagram:

• The length of Plot C is the same as the length of Plot B, which is $30 \text{ m}$.
• The width of Plot C is $20 \text{ m}$.

$$\text{Area}_C = \text{length} \times \text{width} = 30 \text{ m} \times 20 \text{ m} = 600 \text{ m}^2$$

$$\text{Total Area} = \text{Area}_A + \text{Area}_B + \text{Area}_C$$ $$\text{Total Area} = 2000 \text{ m}^2 + 900 \text{ m}^2 + 600 \text{ m}^2$$ $$\text{Total Area} = 3500 \text{ m}^2$$

The total area of the three plots A, B, and C is $3500 \text{ m}^2$.