Given 2x-y+1=0  is a tangent to the hyperbola x2a2−y216=1, then which of the following cannot be sides of right angled triangle

Given 2x-y+1=0  is a tangent to the hyperbola x2a2−y216=1, slope of the tangent is 2y=2x±a2×4−162x−y+4a2−16=0Comparing 4a2=17 it gives a=172Hence, 2a2=17only one triplet 17,4,1 are sides of right angled triangle.