Rounding error with `f64::from_str_radix`

Consider the following program:
```rust
use num::Num;

fn main() {
    let y = "2.89".parse::<f64>();
    println!("{:?}", y);
    let x = f64::from_str_radix("2.89", 10);
    println!("{:?}", x);
}
```
It prints:
```
Ok(2.89)
Ok(2.8899999999999997)
```
Am I missing anything here or results should be equal?