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 7615 views around the world You can reuse this answer Creative Commons License