Angle Relationships in Intersecting and Parallel Lines

Feedback: Not quite! Vertically opposite angles are always equal. If one angle is $50^\circ$, its vertically opposite angle is also $50^\circ$.

Feedback: Not quite! Adjacent angles on a straight line are supplementary, meaning they add up to $180^\circ$. Subtract $120^\circ$ from $180^\circ$ to find $y$: $y = 60^\circ$.

Feedback: Not quite! Co-interior angles are supplementary, meaning they add up to $180^\circ$. Subtract $110^\circ$ from $180^\circ$ to find the other angle: $70^\circ$.

Feedback: Not quite! Alternate angles are always equal. If one alternate angle is $75^\circ$, the other is also $75^\circ$.

Feedback: Not quite! Corresponding angles are always equal. If one angle is $140^\circ$, its corresponding angle is also $140^\circ$.

Feedback: Not quite! Co-interior angles are supplementary, meaning they add up to $180^\circ$. Set $3x + 6x = 180$, then get $9x = 180$. Divide both sides by $9$ to find $x = 20$. Substitute $x = 20$ into the larger angle, $6x$: $6 \times 20 = 120^\circ$.