Back to Use special triangles and unit circle — Problem 1 · Task Set 68

Exercises: Exact Trigonometric Values from Special Triangles

Use special triangles and unit circle symmetry. Express all answers in exact form (no decimals).

Grade 9·22 problems·~30 min·Common Core Math - HS Functions·group·hsf-tf-a-3

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Fluency Practice

Find the exact value. Show the special triangle you used.

$45-45-90 triangle inscribed in the unit circle with legs sqrt(2)/2 and hypotenuse 1$

A 45-45-90 triangle is placed in the unit circle with its hypotenuse along the radius to angle $\frac{\pi}{4}$ . Each leg has length $\frac{\sqrt{2}}{2}$ . What is $\cos\!\left(\frac{\pi}{4}\right)$ ?