## Algebra and Trigonometry 10th Edition

Angle in Radians: $\frac{\pi}{4}$ Value: $\frac{\sqrt 2}{2}$
Note: To convert between degrees and radians use the following formula: $\frac{1^{o}}{}$$\frac{\pi}{180}=\frac{radians}{} We are given that there is 45^{o}. Using the above formula, the equivalence in radians is : \frac{45^{o}}{}$$\frac{\pi}{180}$=$\frac{\pi}{4}$ Using the unit circle, we know that cos($45^{o}$) = $\frac{\sqrt 2}{2}$