To solve this problem, we need to calculate the area of the compound shape. The shape consists of a rectangle with a triangle cut out from the top of it.

Step-by-Step Solution:

1. Find the area of the rectangle:

   The rectangle has a width of 20 cm and a height of 12 cm.

   $\text{Area of the rectangle} = \text{width} \times \text{height} = 20 \, \text{cm} \times 12 \, \text{cm} = 240 \, \text{cm}^2$

2. Find the area of the triangle:

   The triangle has a base of 9 cm and a height of 8 cm.

   $\text{Area of the triangle} = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 9 \, \text{cm} \times 8 \, \text{cm} = \frac{1}{2} \times 72 \, \text{cm}^2 = 36 \, \text{cm}^2$

3. Find the area of the compound shape:

   To find the area of the compound shape, we subtract the area of the triangle from the area of the rectangle:

   $\text{Area of the compound shape} = \text{Area of the rectangle} - \text{Area of the triangle} = 240 \, \text{cm}^2 - 36 \, \text{cm}^2 = 204 \, \text{cm}^2$

Final Answer:

The area of the compound shape is 204 cm².

Would you like more details on this solution, or do you have any other questions?

Related Questions:

1. How do you calculate the area of a compound shape with multiple cutouts?
2. What is the formula for finding the area of a triangle?
3. How do you calculate the perimeter of a compound shape?
4. How would the solution change if the dimensions of the shapes were doubled?
5. How do you find the area of a circle cut out from a rectangle?

Tip: Always break down compound shapes into simpler parts to calculate the area more easily.