what is the perimeter of a quadrilateral with vertices at (-5,-2),(-4,-2),(-5,1), and (-4,1) enter the answer in the box​

Use stokes' theorem to evaluate c f · dr where c is oriented counterclockwise as viewed from above. f(x, y, z) = xyi + 5zj + 7yk, c is the curve of intersection of the plane x + z = 8 and the cylinder x2 + y2 = 81.