The problem asks which of the given strip models represents 90%. Each strip model has 10 equal parts.

1. Problem Description

The problem asks which of the given strip models represents 90%. Each strip model has 10 equal parts.

2. Solution Steps

To find the strip model representing 90%, we need to determine which strip has 9 out of 10 parts shaded.

$90\% = \frac{90}{100} = \frac{9}{10}$

The first strip model has 9 out of 10 parts shaded. Thus, it represents $\frac{9}{10}$ or 90%.

The second strip model has 6 out of 10 parts shaded. Thus, it represents $\frac{6}{10}$ or 60%.

The third strip model has 9 out of 10 parts shaded. Thus, it represents $\frac{9}{10}$ or 90%.

Therefore, the first and the third strip models represent 90%. However, the question is asking for "Which model shows 90%?". So the answer is the first one on the list.

3. Final Answer

The first strip model.