A circle has a chord that goes from ( 2 pi)/3 2π3 to (17 pi) / 12 17π12 radians on the circle. If the area of the circle is 9 pi 9π, what is the length of the chord?

1 Answer
Oct 16, 2016

Length of chord is 6sin((3pi)/8)6sin(3π8)

Explanation:

Central angle =(17pi)/12-(2pi)/3=(17pi)/12-(8pi)/12=(9pi)/12=(3pi)/4=17π122π3=17π128π12=9π12=3π4
Half central angle=(3pi)/8=3π8
If area of circle is 9pi9π then we calculate the radius
pir^2=9piπr2=9π so r^2=9r2=9 and r=3r=3
Length of chord =2rsin(theta/2)2rsin(θ2) where theta θ is the central angle
So length of chord =2*3*sin((3pi)/8)=6sin((3pi)/8)=23sin(3π8)=6sin(3π8)