$27.$

$($a$)$ If the first$-$order maximum for monochromatic light falling on a double slit is at an angle of $10\mathrm{.}010\mathrm{.}0,$ at what angle is the second$-$order maximum? $($b$)$ What is the angle of the first minimum? $($c$)$ What is the highest$-$order maximum possible here?