Source: Previous Question Papers

In the adjoining figure line ll|| line mm and line pp is the transversal. Observe the figure and find the value of w\angle w.

Question Illustration

Options

Option A is correct

4545^{\circ}

Option B

135135^{\circ}

Option C

130130^{\circ}

Option D

9090^{\circ}

Explanation

Let's interpret the given angle positions. Let the transversal intersect line ll at point AA and line mm at point BB. Angle 3x3x is exterior above line ll. Let's assume it's the top-left exterior angle. Angle xx is interior below line ll. For a valid solution, we assume it's the bottom-right interior angle at line ll. The interior angle adjacent to the exterior angle 3x3x (top-left) is 1803x180^{\circ} - 3x. This is the top-left interior angle. Since lines ll and mm are parallel, the alternate interior angles are equal. The top-left interior angle and the bottom-right interior angle are alternate interior angles. Therefore, 1803x=x180^{\circ} - 3x = x. 180=4x180^{\circ} = 4x x=1804x = \frac{180^{\circ}}{4} x=45x = 45^{\circ}. Now, angle ww is interior below line mm. Let's assume it's the bottom-right interior angle at line mm. Since lml || m, the corresponding angles are equal. The bottom-right interior angle at line ll is xx, and the bottom-right interior angle at line mm is ww. Therefore, w=xw = x. Substituting the value of xx, we get w=45w = 45^{\circ}.