Question 1: Calculate the value of angle x if the co-interior angles are supplementary and one of the angles measures 65°.

Answer: 115

Question 2: In a pair of parallel lines cut by a transversal, one co-interior angle measures 120°. Find the measure of its supplementary co-interior angle.

Answer: 60

Question 3: Construct a diagram on the grid showing two parallel lines cut by a transversal, with one co-interior angle of 85°. Label all relevant angles.

Answer: label angles 95° and 85°

Question 4: A transversal cuts two parallel lines. One co-interior angle is 70°. What is the measure of the other co-interior angle on the same side?

Answer: 110

Question 5: Using the property that co-interior angles sum to 180°, solve for x: one angle measures 3x + 20°, and its partner is 2x + 100°.

Answer: 60

Question 6: In a diagram with parallel lines cut by a transversal, the angles labeled A and B are co-interior. If A = 130°, find B.

Answer: 50

Question 7: Explain why co-interior angles on parallel lines always sum to 180° with a brief reasoning.

Answer: Because they are supplementary angles formed on a straight line when a transversal crosses parallel lines.

Question 8: Given two parallel lines and a transversal, if one co-interior angle is 95°, what is the measure of the other co-interior angle on the same side?

Answer: 85

Question 9: A pair of co-interior angles are in a real-world scenario where one angle is 45°. If the angles are on the same side of the transversal, find the other.

Answer: 135

Question 10: Identify the common mistake students make when calculating co-interior angles and suggest how to avoid it.

Answer: Confusing supplementary with equal angles; remember co-interior angles are supplementary, not equal.

Question 11: If a student incorrectly states that co-interior angles are always equal, identify and correct this misconception.

Answer: Co-interior angles are supplementary, not necessarily equal, unless they are 90°.