Secant is a trigonometric function that quantifies the quotient of hypotenuse and the side that is adjacent to the given angle. This is the reciprocal of the cosine function.                       cosine = adjacent / hypotenuse = x/h                       secant = h / x Secant equal to -1 means that x and h are numerically equal but opposite in sign.                     secant = -1                  cosine = 1/secant =1/-1 = -1                      arccos (-1) = 180° Thus, the answer to this item is 180°.