The exterior angles of any polygon have sum 360°. 3 of them are 15°, 25° and 70° and the other (n-3) exterior angles are 50° each. Sum of exterior angles = 15°+25°+70°+(n-3)*50° = 360° 110°+(n-3)*50° = 360° (n-3)*50° = 250°n-3 = 5 n = 8 So the polygon has 8 sides. Edwin