Assume that $C(x)$ is in dollars and $x$ is the number of units produced and sold. For the total$-$cost function $C(x)=0\mathrm{.}01x^2+0\mathrm{.}4x+40,$ find $C$ and $C^{\text{'}}(x)$ when $x=90$ and $x=1.$

$C=$$$$

$($Simplify your answer. Type an integer or decimal rounded to two decimal places as needed.$)$

$C^{\text{'}}(x)$ when $x=90$ is $ per unit.

$($Type an integer or a decimal.$)$