Answer:
3.92699081699
Step-by-step explanation:
[tex]\frac{5(3.14)}{4}\\[/tex]=15.7/4
-sqrt(2)/2
5pi/4 lies in the third quadrant with basic angle: 5pi/4 - pi = pi/4
sin(pi/4) = sqrt(2)/2
Since it's in quadrant 3, sin would be negative
sin(5pi/4) = -sqrt(2)/2
sqrt: square root
