Points (2 ,4 )(2,4) and (4 ,9 )(4,9) are (3 pi)/4 3π4 radians apart on a circle. What is the shortest arc length between the points?

1 Answer
Feb 4, 2018

Shortest Arc length s = r * theta = color(green)(6.8669s=rθ=6.8669

Explanation:

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Chord c = sqrt((4-2)^2 + (9-4)^2) = 5.3852c=(42)2+(94)2=5.3852

radius r = c / (2 sin (theta/2)) = 5.3852 / (2 * sin ((3pi)/8) = 2.9144r=c2sin(θ2)=5.38522sin(3π8)=2.9144

Shortest Arc length s = r * theta = 2.9144 * ((3pi)/4) = color(green)(6.8669s=rθ=2.9144(3π4)=6.8669