30 Degree

45 Degree

60 Degree

90 Degree

degree of accuracy required

method of setting out the perpendiculars and nature of ground

scale of plotting

all of these

45 Degree only

90 Degree only

either 45 Degree or 90 Degree

any angle

method of perpendicular offsets

method of oblique offsets

method of ties

all involve equal measurement on the ground

1 in 100

1 in 250

1 in 500

1 in 1000