To determine the perimeter of the triangle given the vertices, calculate the distances between pair of points. For the first pair (-5,1) and (1,1), the distance is 6. For the next pair, (1,1) and (1, -7), the distance is 8. Lastly, for the pair of points (-5,1) and (1, -7), the distance is 10. Adding all the distance will give the perimeter of the triangle. Thus, the perimeter is 24.