AB =AC triungi isoscel; AC =24 cm ;P =50cm
P =2AB +24
50 =2AB +24
2AB =50-24
2AB =26
AB =13 cm
notam BD inaltime ;BD perpendicular pe AC ;rez. triunghiul ADB dretunghic
AD =AC/2 =24/2 =12cm
AB^2 =AD^2 +BD^2
13^2 =12^2 +BD^2
BD^2 =13^2- 12^2
BD ^2 =169-144
BD^2 =25
BD = 5 cm