In a parallelogram, opposite angles are equal, and adjacent angles are supplementary (i.e., their sum is $180^\circ$).

Given:

• One angle = $60^\circ$

1. Opposite angle: In a parallelogram, opposite angles are equal, so the opposite angle is also $60^\circ$.

2. Adjacent angle: Adjacent angles in a parallelogram are supplementary, meaning their sum is $180^\circ$. Therefore, the adjacent angle is: $180^\circ - 60^\circ = 120^\circ$

Thus, the opposite angle is $60^\circ$ and the adjacent angle is $120^\circ$.

Would you like more details or have any questions?

Here are some related questions:

1. What is the sum of the interior angles of a parallelogram?
2. How do we prove that adjacent angles of a parallelogram are supplementary?
3. Can a parallelogram have all angles equal? What type of parallelogram would that be?
4. What other properties of a parallelogram can be derived from its angles?
5. How would the problem change if one angle was $90^\circ$?

Tip: In any quadrilateral, the sum of all interior angles is always $360^\circ$.