Two straight fences meet at point A and a field lies between them. A horse is tied to a post, P, by a rope of length r metres. Point D is on one fence and point E is on the other, such that PD=PE=PA=r and DPE = 0 radians. This is shown in the following diagram. The length of the arc DE shown in the diagram is 28 m. 7d. Hence, find the size of DE. [2 marks] A new fence is to be constructed between points B and C which will enclose the field, as shown in the following diagram. 800 m A fence B Point C is due west of B and AC = 800 m. The bearing of B from A is 195.