Use a reference angle to write sec255∘ in terms of the secant of a positive acute angle. Do not include the degree symbol in your answer. For example, if the answer is sec(10∘), you would enter sec(10).

sec (75) or csc (15)

Step-by-step explanation:

255 is in the 3rd quadrant where the secant is. Here, the tangent and cotangent is positive.

Reference angle for 255 is,

255 - 180 = 75 degrees.

Therefore, sec (255) = sec (75)

= csc (90 - 75) = csc (15)