How do you know if #sin 30 = sin 150#? Trigonometry Right Triangles Trigonometric Functions of Any Angle 1 Answer Alan P. Feb 13, 2015 #30^o# and #150^o# are reflections of each other in the Y-axis. So #sin 30^o = sin 150^o# 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 show that #(costheta)(sectheta) = 1# if #theta=pi/4#? How do you use the unit circle to find values of #cscx#, #secx# and #cotx#? See all questions in Trigonometric Functions of Any Angle Impact of this question 25078 views around the world You can reuse this answer Creative Commons License