How do you find the exact values #sin (pi/4)# using the special triangles? Trigonometry Right Triangles Special Right Triangles 1 Answer Alan P. · Jim H Aug 4, 2015 #sin(pi/4) = 1/sqrt2 = sqrt2/2# Explanation: #pi/4# is one of the "special triangle" angles: By definition #color(white)("XXXX")##sin = ("opposite")/("hypotenuse")# Answer link Related questions What are the Special Right Triangles? What are the basic properties of a 45-45-90 triangle? What are the basic properties of a 30-60-90 triangle? How do the Special Right Triangles relate to the Unit Circle? How do you find the other two side of a right triangle ABC, if #∠B=60# and #AB=12# where AB is... How do you use special right triangles to find the missing side lengths? Why do you need to use special right triangles? How do you know when to use the special right triangles? What is the length of the shorter diagonal of the parallelogram if the lengths of the two... What is the length of the hypotenuse, in a 30-60-90 triangle the length of the shorter leg... See all questions in Special Right Triangles Impact of this question 10677 views around the world You can reuse this answer Creative Commons License