Answer:
x = 90
y = 30°
∠ABC = 75°
Explanation:
Finding the angles of isosceles triangle:
ΔDAB is an isosceles triangle.
⇒ ∠ADB ≅ ∠ABD = y
In ΔABD ,
120 + y + y = 180 {Angle sum property of triangle}
120 + 2y = 180
2y = 180 - 120
2y = 60
y = 60 ÷ 2
ΔDCB is an isosceles triangle.
∠CDB ≅ ∠CBD = 45
x + 45 + 45 = 180
x + 90 = 180
x = 180 - 90
∠ABC = ∠ABD + ∠DBC
= 30 + 45
= 75°