Splitting a Triangular Density in Half

The distance $X$ covered by a single rented e-scooter trip, measured in kilometres, is a continuous random variable on $[0, 4]$. Short trips are the most common, and the probability density function falls off in a straight line:

$f(x) = k\,(4 - x) \quad \text{for } 0 \le x \le 4, \qquad f(x) = 0 \ \text{ otherwise}$

where $k$ is the constant that makes $f$ a valid PDF.

The operator wants the distance $m$ at which the cumulative distribution function reaches one half — that is, the value of $m$ satisfying

$P(X \le m) = 0.5$

Find $m$ in kilometres, rounded to 3 decimal places. Enter the number only, without the unit.