Clock angle — What is the (smaller) angle between the minute and hour hands at exactly 2:45?
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A180°
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B190°
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C175°
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DNone of these
Answer
Correct Answer: None of these
Explanation
Introduction / Context:We compute the smaller angle between the hands at 2:45 using standard formulas.
Given Data / Assumptions:
- At 2:45 → h = 2, m = 45.
- Hour angle = 30h + 0.5m; minute angle = 6m.
Concept / Approach:Angle difference = |(30h + 0.5m) − 6m|; report the smaller angle.
Step-by-Step Solution:Hour angle = 30*2 + 0.5*45 = 60 + 22.5 = 82.5.Minute angle = 6*45 = 270.Difference = |82.5 − 270| = 187.5 degrees.Smaller angle = 360 − 187.5 = 172.5 degrees.
Verification / Alternative check:Using the compact formula |30h − 5.5m| also yields |60 − 247.5| = 187.5 → smaller 172.5.
Why Other Options Are Wrong:180°, 190°, 175° are nearby round values but not exact; correct is 172.5°.
Common Pitfalls:Reporting the reflex angle (187.5°) instead of the smaller one, or rounding to 180°.
Final Answer:172.5°, which is not listed; hence “None of these.”