Answer
$CB=15.2 cm$
Work Step by Step
We are given that $MN=7.6$ and the $MN$ is the mid-segment of $\triangle ABC$. Since $MN$ is the mid-segment, then...
$MN= \frac{1}{2} BC$
Substitute in known values...
$7.6=\frac{1}{2} BC$
Multiply both sides by 2...
$15.2=BC$
