Question

In the diagram below AB is parallel to CD what is the value of y?

Answer 1

y° = y₁° (opposite or Vertical angles), but y₁ = 45° corresponding angles,


then y = 45°

Answer 2

The value of y is 45°

Solution-

When two lines are crossed by another line (i.e the transversal), a pair of angles

1. on each of those two lines
2. on opposite sides of the transversal
3. but outside those two lines

are called Alternate Exterior Angles.

When the two lines are parallel Alternate Exterior Angles are equal.

So, in this case the two highlighted angles are Alternate Exterior Angles and as given that AB || CD, so y=45°