Answer:
y = 20
Step-by-step explanation:
Since AB and AC are congruent then the triangle is isosceles, thus
∠B = ∠C = 25°
To find ∠A subtract the sum of the 2 angles from 180°
∠A = 180° - (25 + 25)° = 180° - 50° = 130°, thus
3y + 70 = 130 ( subtract 70 from both sides )
3y = 60 ( divide both sides by 3 )
y = 20
