At what distance behind a broken-down passenger car, parked on a motorway, should you place a warning triangle?

Why?

On a motorway, the warning triangle must be placed 100 m behind the immobilised vehicle to give approaching drivers advance warning. The photo shows a triangle behind the car, but the required distance cannot be judged from the image's perspective. The 30-50 m distance applies in relevant situations on other roads outside built-up areas; 150 m is not the distance required here.

art. 50 ust. 2 pkt 1 lit. b Prawa o ruchu drogowym