In the given figure, AB || CD, CD || EF
and y : z = 3 : 7.
Let y = 3a and z = 7a
∠DHI = y (vertically opposite angles)
∠DHI + ∠FIH = 180°
(Interior angles on the same side of the transversal)
⇒ y + z = 180°
⇒ 3a + 7a = 180°
⇒ 10a = 180° ⇒ a = 18°
∴ y = 3 × 18° = 54° and z = 18° × 7 = 126°
Also, x + y = 180°
⇒ x + 54° = 180°
∴ x = 180° – 54° = 126°
Hence, x = 126° Ans.
