### Numerical approximation of symbolic equation

What I would like to do is the following:

var('theta')

```
theta
```

theta=25*units.angles.degree

print theta

```
25*degree
```

a=sin(theta)

print a

```
sin(25*degree)
```

At this point, I type 'a.' and tab and in the popup list of functions I find numerical_approx. So I type in:

a.numerical_approx()
Traceback (click to the left of this block for traceback)

```
...
TypeError: cannot evaluate symbolic expression numerically
```

Okay, it would appear that adding the units to theta turns it into a symbolic variable which turns my expression a into a symbolic expression. But what I would like to do is enter my angle theta in either degrees or radians and get a numerical approximation of the answer based on the units of the input. Is there a clean way to do this?