A circular flower bed of radius 1.2m is in a garden. A stake is fixed at a point P on the ground such that OP=180cm, where O is the centre of the flower bed. A straight plank is to be placed from P so that it just touches the rim of the flower bed at T.
(i) Convert the distance OP into metres.
(ii) Calculate the exact length PT of the plank, in metres.
(iii) Express your answer in centimetres, correct to the nearest centimetre.