∠POQ and ∠QOR from linear pair of angles. The sum of ∠POQ and ∠QOR is ___________.
180
Linear pair of angles is a pair of angles which have a common arm and the sum of the angles = 180∘. Therefore, if ∠POQ and ∠QOR form a linear pair, then the sum of the pair of angles should be equal to 180∘.