If two parallel lines are cut by a transversal, then the Corresponding Angles are congruent.
If a transversal intersects two lines and the corresponding angles are congruent, then the lines are parallel.

In the above figure, CG||DH and AF is the transversal cutting the two parallel lines. The pairs of corresponding angles ∠ABC and ∠BED, ∠CBE and ∠DEF, ∠ABG and ∠BEH, and ∠GBE and ∠HEF are equal.

A. 60°, 30° and 30°
B. 30°, 30° and 32°
C. 58°, 32° and 32°
D. None of the above
Correct Answer: C
Step 1: From the figure, ∠x and 58°, ∠y and ∠z form corresponding angles.
Step 2: ∠x = 58° [Corresponding angles are equal.]
Step 3: ∠z + 90° + 58° = 180°
Step 4: So, ∠z + 148° = 180°
Step 5: ∠z = 180° - 148° = 32°
Step 6: ∠z = ∠y [Corresponding angles are equal.]
Step 7: ∠y = 32°
Q1: If two parallel lines are cut by a transversal, which of the following is true?
Q2: In a diagram where a transversal intersects two lines, ∠1 and ∠5 are corresponding angles. If m∠1 = 70°, and the lines are parallel, what is m∠5?
Q: What is a transversal?
A: A transversal is a line that intersects two or more other lines.
Q: Are corresponding angles always congruent?
A: No, corresponding angles are only congruent if the two lines intersected by the transversal are parallel.