How many significant digits are there in `7521.05890`?

Explanation

To determine the number of significant digits in the number `7521.05890`, we can follow these steps:

### Step 1: Identify Non-Zero Digits
All non-zero digits are always considered significant. In the number `7521.05890`, the non-zero digits are 7, 5, 2, 1, 5, 8, and 9.

**Count of Non-Zero Digits:**
- 7
- 5
...