If the direction ratio of two lines are given by `3lm-4ln+mn=0 and l+2m+3n=0`, then the angle between the lines, is

If the direction ratios of two lines are given by 3lm-4ln+mn=0 and l+2m+3n=0 then the angle between the lines is

If the direction rations of two lines are given by 3lm-4ln+mn = 0 and l + 2m + 3n = 0 then the angle between the lines is

If the direction ratios of two lines are given by l+m+n=0, mn-2n+lm=0 , then the angle between the lines is

If the direction cosines of two lines are given by l+m+n=0 " and " l^(2)-5m^(2)+n^(2)=0 then the angle between them is