Give an example for vertically opposite angles in your surroundings.

If the complement of the following angle is $k°$ then find $k$.

Find the complement of the following angle. Give the answer in degree $\left(°\right)$.

Find the supplement of the angle. Give the answer in degree $\left(°\right)$.

In the given figure, $\mathbf{\angle }1\mathbf{}$ and $\mathbf{}\mathbf{\angle }2\mathbf{}$ are supplementary angles. If $\mathit{\angle }1$ is decreased, what changes should take place in $\mathit{\angle }2$ so that both the angles still remain supplementary.