Answer
The angle between the vectors is acute.
Work Step by Step
Since $$\langle \frac{12}{5},-\frac{4}{5}\rangle \cdot \langle \frac{1}{2},-\frac{7}{4}\rangle =\frac{12}{10}+\frac{7}{5}=\frac{11}{5}\neq0 $$ then the vectors are not orthogonal. The angle between the vectors is acute since their dot product is positive (positive cosine of the dot product indicates that we are in the 1st quadrant).
