A circle has a chord that goes from ( pi)/2 π2 to (3 pi) / 4 3π4 radians on the circle. If the area of the circle is 96 pi 96π, what is the length of the chord?

1 Answer
Apr 7, 2017

length of chord ~~ 7.4997.499

Explanation:

enter image source here

Area of a circle A=pir^2A=πr2,
Given A=96pi, => r=sqrt96A=96π,r=96

As shown in the figure, the angle thetaθ subtended by the chord at the centre is :
theta=(3pi)/4-pi/2=pi/4θ=3π4π2=π4
=> theta/2=pi/8θ2=π8

=> AM=rsin(theta/2)AM=rsin(θ2)

=> length of chord AB=2AM=2*r*sin(theta/2)AB=2AM=2rsin(θ2)
= 2*sqrt96*sin(pi/8)~~7.499=296sin(π8)7.499