If AB || CD in the figure, then the value of x + y is:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 85°
When a transversal cuts two parallel lines, corresponding angles are equal, and two angles on a straight line (a linear pair) add up to \(180^\circ\).
The angle \((2x-10)^\circ\) below CD on the left of EF has a corresponding angle below AB on the left of EF, so that angle is also \((2x-10)^\circ\)
At AB it forms a linear pair with \((2y+20)^\circ\): \((2x-10)+(2y+20)=180\)
\(2x+2y=170\)
\(x+y=85^\circ\)