A Bicycle Pedal Is Pushed by a Foot with a Force

Short Answer

A bicycle pedal is pushed by a foot with a force of $a - \mathrm { N }$ as shown. The shaft of the pedal is $12 \mathrm {~cm}$ long.
Find the magnitude of the torque about $P$ correct to two decimal places.
Let $a = 70 , b = 70 ^ { \circ } , c = 10 ^ { \circ }$ .