Ricky travels 5 km in a straight line from home (assume standard convention: initial heading North), then takes a right turn and goes 6 km, then takes a left turn and goes 3 km. What is his straight-line distance from home now?
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A10 km
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B12 km
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C9 km
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D11 km
Answer
Correct Answer: 10 km
Explanation
Introduction / Context:The original statement does not specify the first direction. Under the standard recovery convention for such items, we assume the first leg is due North. After that, a right turn leads to East, and a subsequent left brings the heading back to North. We must compute the net displacement.
Given Data / Assumptions:
- Assumed initial heading: North (5 km).
- Right turn → East (6 km).
- Left turn from East → North (3 km).
- Compute straight-line distance from home to the final point.
Concept / Approach:Sum orthogonal components. North–South total: 5 + 3 = 8 km North. East–West total: 6 km East. Use the Pythagorean theorem for the resultant.
Step-by-Step Solution:
Vertical component: 8 km North.Horizontal component: 6 km East.Distance d = sqrt(8^2 + 6^2) = sqrt(64 + 36) = sqrt(100) = 10 km.Verification / Alternative check:The legs 6 and 8 form another well-known Pythagorean triple with hypotenuse 10.
Why Other Options Are Wrong:9, 11, or 12 km do not satisfy the relation d^2 = 6^2 + 8^2 for orthogonal movement.
Common Pitfalls:Assuming a different initial heading without stating it; the Recovery-First Policy permits the standard North assumption when unspecified.
Final Answer:10 km