Which of the following minor instruments are used for setting out right angles in chain surveying?
1. Cross staff
2. Optical square
3. Prism square
4. Auto level
1
1 and 2 only
2
2 and 3 only
3
1, 2 and 3
4
2, 3 and 4 only
Which of the following minor instruments are used for setting out right angles in chain surveying?
1. Cross staff
2. Optical square
3. Prism square
4. Auto level