Quad display question

I have a question  regarding a gigabyte 270x oc 4gb card. I currently have 3 displays plugged in two via DVI one via HDMI to DVI and that leaves one DisplayPort plug. Id like to run a 4th display (my 47" tv) but unsure on what cable or adapter to buy. i would love to keep it simple with a passive dp to hdmi 15ft cable but not sure if it will work for this application or if I have to run an active DP to HDMI adapter then a HDMI to HDMI cable.