Answer
$emf = 51~mV$
Work Step by Step
We can find the induced emf:
$emf = -\frac{d\Phi}{dt}$
$emf = -A~\frac{dB}{dt}$
$emf = -(\pi~r^2)~(\frac{dB}{dt})$
$emf = -(\pi)~(0.037~m)^2~(-\frac{76\times 10^{-3}~T}{4.5\times 10^{-3}~s})~cos~45^{\circ}$
$emf = 51~mV$
