Let the three angles be \(x, 2x,\) and \(3x\) respectively. Since opposite angles of a cyclic quadrilateral are supplementary, Therefore, \(x + 3x = 180^\circ\) i.e., \(4x = 180^\circ\) So, \(x = 45^\circ\) \(\therefore 3x = 3 \times 45^\circ = 135^\circ\) \(\therefore\) The measures of the first and third angles are \(45^\circ\) and \(135^\circ\) respectively.