How do you evaluate sec 780? Trigonometry Right Triangles Trigonometric Functions of Any Angle 1 Answer Nghi N Dec 24, 2016 2 Explanation: sec (780) = 1/(cos 780). Find cos (780). cos (780) = cos (60 + 2(360)) = cos 60 Trig table gives: cos 60 = 1/2. There for: sec 780 = 1/(cos 60) = 2 Answer link Related questions How do you find the trigonometric functions of any angle? What is the reference angle? How do you use the ordered pairs on a unit circle to evaluate a trigonometric function of any angle? What is the reference angle for 140^\circ? How do you find the value of cot 300^@? What is the value of sin -45^@? How do you find the trigonometric functions of values that are greater than 360^@? How do you use the reference angles to find sin210cos330-tan 135? How do you know if sin 30 = sin 150? How do you show that (costheta)(sectheta) = 1 if theta=pi/4? See all questions in Trigonometric Functions of Any Angle Impact of this question 8131 views around the world You can reuse this answer Creative Commons License