Answer
The force exerted by the incisors is $83.3~N$
Work Step by Step
The torque exerted by the muscle about the joint is equal in magnitude to the torque exerted by the incisors about the joint.
We can find the force $F_i$ exerted by the incisors:
$r_i~F_i = r_m~F_m$
$F_i = \frac{r_m~F_m}{r_i}$
$F_i = \frac{(2.5~cm)(220~N)}{6.6~cm}$
$F_i = 83.3~N$
The force exerted by the incisors is $83.3~N$
