A circle has a center at (7 ,5 )(7,5) and passes through (1 ,2 )(1,2). What is the length of an arc covering (3pi ) /4 3π4 radians on the circle?

1 Answer
Jan 21, 2016

(9pi*sqrt(5))/49π54

Explanation:

The circle's radius is
r=sqrt((7-1)^2+(5-2)^2)=sqrt(36+9)=sqrt(45)=3*sqrt(5)r=(71)2+(52)2=36+9=45=35

Since the length of an arc covering 2pi2π radians is 2pi*r2πr, the length of an arc covering xx radians is
"Arc's Length"=cancel (2pi)r*(x/(cancel(2pi)))=x*r

In case
"Arc's Lenght"=(3pi)/4*3*sqrt(5)=(9pi*sqrt(5))/4