In an isosceles triangle, one of the angles is 150 degrees. Find the largest outer angle of the triangle (in degrees)

If one of the angles in an isosceles triangle is 150º, then this angle cannot be one of the equal angles. Since the sum of the interior angles of a triangle is 180 °, the sum of two equal angles is 180 ° – 150 ° = 30 °. This means that each inner angle at the base of the triangle is 30 °: 2 = 15 °. So, the interior angles are equal: 150º, 15º and 15º. As you know, the outer corner of a triangle is an angle adjacent to any of the inner corners of the triangle. Let’s calculate the degree measures of external angles: one external angle 180 ° – 150 ° = 30 °, and two external angles 180 ° – 15 ° = 165 °.
Answer: 165 °.