Roberta, who is 1.6 metres tall, is using a mirror to determine the height of a building. She knows that the angle of elevation is equal to the angle of reflection when a light is reflected off a mirror. She starts walking backwards from the building until she is 14.6 metres away and places the mirror on the ground. She walks backwards for 1.4 metres more until she sees the top of the building in the mirror. What is the height of the building