Since XC = CZ are radii, triangle XCZ is isosceles. Therefore, angle CXO = angle CZO. Also, the sum of angles in triangle XCZ is 180°. So, angle CXO + angle CZO + angle XCZ = 180°. We know angle XCZ = 50°. Therefore, 2 * angle CXO + 50° = 180°. This gives 2 * angle CXO = 130°, and angle CXO = 65°. Angle XOZ is twice the inscribed angle CXO, so angle XOZ = 2 * 65° = 130°.
Step 2: Find the measure of angle XYZ
Angle XCZ is the central angle subtended by arc XZ. Angle XYZ is an inscribed angle subtended by the same arc XZ. The measure of an inscribed angle is half the measure of the central angle subtended by the same arc. Therefore, angle XYZ = angle XCZ / 2 = 50°/2 = 25°.