Step-by-step explanation:
the sum of all angles in any triangle is always 180°.
and an isosceles triangle has 2 equal sides and as such also 2 equal angles.
the 162° Antje cannot be one of them, because 2×162 is way bigger than 180.
so, that means the other 2 angles must be equal. and again, all 3 together must be 180°
180 = 162 + 2×angle
2×angle = 18
angle = 9°