First we need to find the measurement of arc PQ.
And sum of measurement of all arc angles is 360 degree.
Let measurement of arc PQ is x degree.
Therefore, we get

So measurement of arc PQ is 72.
And measurement of arc PQR is the sum of the measurement of arc PQ and QR.
That is

measurement of Arc PQR = 137 degree= 2.39 radian
And radius is 6.48 inches
And arc length is the product of radius and central angle in radians .
That is
