Alfa + 25 grade = 90 grade
Alfa = 90 - 25 = 65 grade
Alfa + 52 grade = 90 grade
Alfa = 90 - 52 = 38 grade
Alfa + 77 grade = 90 grade
Alfa = 90 - 77 = 13 grade
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Dacă e complementul lui 25 grade, 52 min, 77 sec facem astfel:
alfa + 25° 52' 77 " = 90°
alfa = 90° - 25° 52' 77"
alfa = 89° 60' - 25° 52' 77"
alfa = 89° 58' 120" - 25° 52' 77"
alfa = 64° 6' 43"