Bloodstain pattern analysis at an assault scene documents an elliptical stain measuring 4 mm across its narrow axis and 8 mm along its long axis. Using the standard trigonometric relationship, the approximate angle between the drop's trajectory and the target surface was:
- A 30 degrees ✓
- B 45 degrees
- C 60 degrees
- D 90 degrees
Correct answer: A. 30 degrees
Explanation
Impact angle is calculated as sine theta equal to width divided by length. Here sine theta equals 4 divided by 8, which is 0.5, giving theta of 30 degrees. A circular stain corresponds to 90 degrees, and a 45 degree impact would give a length about 1.4 times the width, not twice. The elongation ratio directly determines the angle, making this a standard reconstruction calculation.
Reference: Knight's Forensic Pathology, 6th ed.
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