A full circle is 360 degrees. When a pizza is cut into 9 equal slices, each slice has an angle of:
\[ \text{Angle of each slice} = \frac{360^\circ}{9} = 40^\circ \]
If you take off 5 slices, that means you have 4 slices left. The angle of the slices left can be calculated by multiplying the number of slices left by the angle of each slice:
\[ \text{Total angle of slices left} = 4 \times 40^\circ = 160^\circ \]
Therefore, the angle of the slices left is 160 degrees.