A light bulb is placed between two plane mirrors inclined at an angle of ${60}^o$ . Number of images formed are 

Two plane mirrors are kept on a horizontal table making an angle $\theta$ with each other as shown schematically in the figure. The angle $\theta$ is such that any ray of light reflected after striking both the mirrors return parallel to its incident path. For this to happen, the value of $\theta$ should be

Write the quadrants in which the following points lie:

$\left(-4,7\right)$