What is the exact value of #sec 210#? Trigonometry Right Triangles Trigonometric Functions of Any Angle 1 Answer Nghi N. May 7, 2015 #sec 210 = 1/cos 210 = 1/cos (30 + 180) = 1/(-cos 30) .# #Since (-cos 30) = (-sqr3)/2#, then #sec 210 = -2/(sqr3) = -(2.sqr3)/3# 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 25182 views around the world You can reuse this answer Creative Commons License