Answer:
25°
Step-by-step explanation:
we can find the value of the angle next to 50° by the rule of supplementary angles, so 180° - 50° = 130°.
next, since the sum of angles in a triangle is 180° and the triangle is an isosceles triangle, we can find angle 1 with (180° - 130°) ÷ 2 = 25°.
i hope this helps! :D