Machine Design Class. Please solve this problem in the most explaining way possible to understand

PROBLEM $2(24$ points$)$

$($a$)$ A $25$ degree pressure angle, $43$ tooth spur gear has a diametral pitch of $8.$ Find the pitch diameter, addendum, dedendum, outside diameter, and circular pitch.

$($b$)$ A $78$ tooth spur gear is in mesh with a $27$ tooth pinion. For a diametral pitch of $6$ in $^(-1)$ and pressure angle of $20$ degrees, find the contact ratio.

$($c$)$ If the gearset in Problem $2$ b transmits $33$ kW at $1600$ rpm by the pinion, find the torque on each shaft.