To find the area of the entire rectangle, we calculate the area of each of the four smaller rectangles and sum them up. The dimensions of the four smaller rectangles are:

1. Top left rectangle: Height = $x$, Width = $x$, Area = $x \cdot x = x^2$
2. Top right rectangle: Height = $x$, Width = $6$, Area = $x \cdot 6 = 6x$
3. Bottom left rectangle: Height = $5$, Width = $x$, Area = $5 \cdot x = 5x$
4. Bottom right rectangle: Height = $5$, Width = $6$, Area = $5 \cdot 6 = 30$

Total Area

Adding these together, we have: $\text{Total Area} = x^2 + 6x + 5x + 30$

Combine Like Terms

$\text{Total Area} = x^2 + (6x + 5x) + 30 = x^2 + 11x + 30$

Thus, the area of the entire rectangle is: $\boxed{x^2 + 11x + 30}$

Let me know if you want a breakdown of each step or have further questions!

Here are 5 related questions to explore:

1. How would the area change if the height and width are increased by a constant value?
2. How do you factorize the polynomial $x^2 + 11x + 30$?
3. Can you explain the role of the distributive property in calculating the total area?
4. How would the result differ if one dimension is negative?
5. How can you graph the polynomial $x^2 + 11x + 30$ and interpret its properties?

Tip: When working with polynomials, always simplify by combining like terms for a clearer standard form.