Hello DeanNadasdy,
Thank you for reaching out Surface Community. You can connect your Surface Pro 5 to a projector via miniDisplay Port on your Surface then on your Projector depends on what ports arer available either HDMI/VGA. Please check this link for connecting Surface to a second screen.
If this works, we highly encourage you to inform our Community by clicking on Yes or marking my post as an answer. This will help other members who may have the same issue as you. Otherwise, don't hesitate to update us so we can further assist you.
Regards,
KarenJune_F