Find the area of the two plane figures shown below. The first figure is L-shaped, and the second figure consists of two stacked rectangles.

Here are the areas of the two plane figures.

For the first figure (L-shaped on the left):
This figure can be divided into two rectangles.

• Step 1: Identify the dimensions of the two rectangles. Divide the L-shape into a left vertical rectangle and a right horizontal rectangle. The left rectangle has a width of $4 \text{ cm}$ and a height of $8 \text{ cm}$. The right rectangle has a height of $3 \text{ cm}$. Its width is the total bottom length minus the width of the left part: $12 \text{ cm} - 4 \text{ cm} = 8 \text{ cm}$.

• Step 2: Calculate the area of the left rectangle.

  $$\text{Area}_{\text{left}} = 4 \text{ cm} \times 8 \text{ cm} = 32 \text{ cm}^2$$

• Step 3: Calculate the area of the right rectangle.

  $$\text{Area}_{\text{right}} = 8 \text{ cm} \times 3 \text{ cm} = 24 \text{ cm}^2$$

• Step 4: Sum the areas to find the total area of the first figure.

  $$\text{Total Area}_1 = 32 \text{ cm}^2 + 24 \text{ cm}^2 = 56 \text{ cm}^2$$

  The total area of the first figure is $\boxed{\text{56 cm}^2}$.

For the second figure (two stacked rectangles on the right):
This figure is composed of two rectangles.

• Step 1: Identify the dimensions of the top rectangle. The top rectangle has a width of $4 \text{ cm}$ and a height of $8 \text{ cm}$.

• Step 2: Calculate the area of the top rectangle.

  $$\text{Area}_{\text{top}} = 4 \text{ cm} \times 8 \text{ cm} = 32 \text{ cm}^2$$

• Step 3: Identify the dimensions of the bottom rectangle. The bottom rectangle has a width of $8 \text{ cm}$ and a height of $3 \text{ cm}$.

• Step 4: Calculate the area of the bottom rectangle.

  $$\text{Area}_{\text{bottom}} = 8 \text{ cm} \times 3 \text{ cm} = 24 \text{ cm}^2$$

• Step 5: Sum the areas to find the total area of the second figure.

  $$\text{Total Area}_2 = 32 \text{ cm}^2 + 24 \text{ cm}^2 = 56 \text{ cm}^2$$