Răspuns :
Sin c=ab /ac
Rad5=ab/ac
Ab=ac*Rad5
T. P. =>ac la 2=ab la 2 +bc la 2
Ac la 2=5*ac la 2 +4*5
Ac la 2=5*ac la 2+20
-4*ac la 2=20
Ac la 2=5
Ac =rad 5
Ab =5
Cosc =cb/ac
Cosc=2rad 5/rad 5
Cos c =2
Tg c =ab/bc
Tg c=5/2rad5
Tg c =5rad 5/10
Ctg c=2rad5/5
Rad=radical
Rad5=ab/ac
Ab=ac*Rad5
T. P. =>ac la 2=ab la 2 +bc la 2
Ac la 2=5*ac la 2 +4*5
Ac la 2=5*ac la 2+20
-4*ac la 2=20
Ac la 2=5
Ac =rad 5
Ab =5
Cosc =cb/ac
Cosc=2rad 5/rad 5
Cos c =2
Tg c =ab/bc
Tg c=5/2rad5
Tg c =5rad 5/10
Ctg c=2rad5/5
Rad=radical