A robot vacuum turned 270° clockwise and then stopped. It was now facing North-East. Which direction was it facing before the turn?
Need a hint?
Count the 45° steps around the compass, and remember you must turn the opposite way to undo the turn.
Worked answer
- The eight directions are 45° apart, so 270° is 270 ÷ 45 = 6 steps.
- Undo the turn by turning 270° anticlockwise from North-East.
- Anticlockwise from North-East: 1 step North, 2 steps North-West, 3 steps West, 4 steps South-West, 5 steps South, 6 steps South-East.
- So before the turn it was facing South-East.
Answer: South-East
The mistake this question tests
Habit
Calculation slip
Pupils who turn the robot clockwise again from North-East, or who forget to reverse the direction, end up at North-West instead of South-East.
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