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What is the magnitude of the position vector with components 9 and 12?
AIt is 21 units
BIt is 11 units
CIt is 15 units
DIt is 25 units
Answer & Solution
Correct answer: C. It is 15 units
1. The magnitude is found by the Pythagorean Theorem on the two components.
2. Squaring gives 81 and 144, which add to 225.
3. The square root of 225 is 15.
4. So the magnitude is 15 units.
5. Answering 21 units adds the components instead of squaring, adding, then taking the root.
_Source: OpenStax Precalculus (CC BY 4.0), Ch 8 "Further Applications of Trigonometry", section 8.8 Vectors_
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