Answer: you compare the fingerprints to the 7 known patterns
Explanation: What are the seven basic fingerprint patterns?
Arches. These occur in about 5% of the encountered fingerprints.
Loops. These can be seen in almost 60 to 70% of the fingerprints that are encountered.
Whorls.
Plain arch.
Tented arch.
Radial loops.
Ulnar loops.
Double loop.