To express the perimeter of a rectangle with length $R$ cm and width $R - 5$ cm (since the width is 5 cm shorter than the length), we can follow these steps:

Formula for the perimeter of a rectangle:

$\text{Perimeter} = 2 \times (\text{Length} + \text{Width})$

Substituting the values:

$\text{Perimeter} = 2 \times (R + (R - 5))$

Simplifying:

$\text{Perimeter} = 2 \times (R + R - 5)$ $\text{Perimeter} = 2 \times (2R - 5)$ $\text{Perimeter} = 4R - 10$

So, the simplified expression for the perimeter of the rectangle is $4R - 10$ cm.

Would you like further details on this?

Here are some related questions to consider:

1. How would the expression change if the width were 5 cm longer than the length?
2. What is the perimeter if $R = 8$ cm?
3. How do you calculate the area of this rectangle?
4. What if both the length and width were decreased by 2 cm?
5. How would the perimeter change if both the length and width were doubled?

Tip: Always double-check if a problem asks for simplification or specific values before finalizing your answer.