An Interval from a Shifted Quadratic CDF

A packaging machine runs for a random length of time $T$, measured in hours, before it needs a reset. $T$ is a continuous random variable that always lies between $2$ and $7$ hours, and its cumulative distribution function $F(t) = P(T \le t)$ is

$F(t) = k\,(t - 2)^2 \qquad \text{for } 2 \le t \le 7$

with $F(t) = 0$ for $t < 2$ and $F(t) = 1$ for $t > 7$. The constant $k$ is whatever value makes $F$ a valid CDF.

What is $P(4 < T \le 6)$?

Give your answer as a decimal probability, rounded to 2 decimal places.