acc to pythagorous theoram, In rt angle triangle a^2 + b^2= c^2 stmt a A^2 + B^2 < 15---- no value for c---insufficient stmt b-c>4 no values for a & b--insufficient combining both,a^2 + b^2<c2....So it must be greater than 90..Hope it helps..IMO C Hello could you explain using values please