The observations from a closed-loop traverse around an obstacle are 

Segment	Observation from station	Length (m)	Azimuth (clockwise from magnetic north)
PQ	P	Missing	33.7500°
QR	Q	300.000	86.3847°
RS	R	354.524	169.3819°
ST	S	450.000	243.9003°
TP	T	268.000	317.5000°

What is the value of the missing measurement (rounded off to the nearest 10 mm)?