These functions provide approximate measures of length, area, and volume of
geometries where relevant. The reason for approximation is that some measures
require square root operations or multiplication by π, both operations where
exactness is necessarily lost. Not all geometries have meaningful measures,
e.g. a direction is dimensionless, a line is without area, and a circle has
no volume. Some geometries are infinite in some measures, e.g. a plane has an
infinite area. The return value will reflect this.

```
approx_length(x)
approx_area(x)
approx_volume(x)
approx_radius(x)
```

## Arguments

- x
A geometry vector

## Examples

```
approx_length(vec(point(1:4, 4:7)))
#> [1] 4.123106 5.385165 6.708204 8.062258
approx_area(circle(point(0, 0), 5:9))
#> [1] 15.70796 18.84956 21.99115 25.13274 28.27433
approx_volume(sphere(point(0, 0, 0), 5:9))
#> [1] 46.83210 61.56239 77.57748 94.78150 113.09734
```