mohon jawab y makasih

∠PQR = ∠RTU
40° = 40°

∠RSU dan ∠SUT = sudut siku-siku atau 90°

4x + (90° + 90° + 40°) = 360°
4x + 220° = 360°
4x = 360° - 220°
4x = 140°
x = 35°