Given

A lever shown below has a length $L=545mm.$ It is attached to the shaft A using a key that has a width $d$ and length of $21$ mm $.$ The shaft is fixed and a vertical force of $205$ N is applied perpendicular to the handle. The shaft has a radius $r=16mm$

Required

Determine the dimension $d$ in mm to the nearest $100$ th$,$ i$.$e$.,$ two $(2)$ decimal places if the allowable shear stress for the key is ${}_{\text{a}\text{l}\text{l}}=42$MPa.