There are 4. Drawn to scale:
BTW, If you meant EXACTLY ONE side 7 cm, not TWO sides 7 cm, and 
EXACTLY ONE angle 50°, not TWO angles 50°, then there is only 
one such isosceles triangle, the upper left one with the base 7 
and the vertex angle 50°.  The others either have TWO sides 7cm or
TWO angles 50° or both.
Edwin