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Angie, I showed you that the measure of angle RSQ is 50^{o}. The sector RSQ is only part of the circle. The entire circle has a central angle of 360^{o} so sector RSQ is a fraction of the circle, in fact the sector is 50/360 = 5/36^{th} of the circle. The entire circumference of the circle has length 2πr where r is the radius and thus the length of the arc QR is 5/36^{th} of this length. Hence the length of the arc QR is
Harley  


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