A savoir:

90° = (Pi/2) radians = 100 grades.
et
1° = 60 minutes
et
1 minute = 60 secondes.
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Avec cela tu dois pouvoir tout faire.
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39° = 39° 0' 0''
---
90° = (Pi/2) radians
1° = (Pi/2)/90 = Pi/180   radians
39° = 39.Pi/180 radians.
39° = 39*3,141592.../180 = 0,680678... radians
---
90° = 100 grades
1° = 100/90 = 10/9 grade
39° = 39*(10/9) = 390/9 = 130/3 grades
39° = 43,3333... grades
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25°12' = 25° 12' 0''
---
25°12':
60' = 1°
1' = (1/60)°
12' = (12/60)°
12' = 0,2°
->
25°12' = 25,2°

90° = (Pi/2) radians
1° = (Pi/2)/90 = Pi/180   radians
25,2° = 25,2.Pi/180 radians.
25,2° = 0,439822971503... radians
25° 12' = 0,439822971503... radians
---
90° = 100 grades
1° = 100/90 = 10/9 grade
25,2° = 25,2*(10/9) = 28 grades.
25° 12' = 28 grades.
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43 grades:
100 grades = 90°
1 grade = 0,9°
43 grades = 0,9*43 = 38,7°
0,7° = 60'*0,7 = 42'
43 grades = 38°42'

90° = (Pi/2) radians
1° = (Pi/2)/90 = Pi/180   radians
38,7° = 38,7*(Pi/180)   radians
38,7° = 0,675442420522   radians
43 grades = 0,675442420522   radians.
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Sauf distraction (je n'ai rien relu), refais les calculs et cherche
le dernier.