Answer: Â [tex]30^{\circ}[/tex]
Step-by-step explanation:
According to the given information:
Minor arc = 150°
Major arc = 360°-150°=210°
Since angle made by tangents is equal to the half of the difference between the major and the minor arcs made by them.
Let x be the viewing angle (angle made by tangents):
Then,
[tex]x=\dfrac{1}{2}(\text{Major arc -Minor arc})\\\\\Rightarrow\ x=\dfrac{210^{\circ}-150^{\circ}}{2}\\\\\Rightarrow\ x=\dfrac{60^{\circ}}{2}\\\\\Rightarrow\ x=30^{\circ}[/tex]
Hence, the viewing angle should be used=[tex]30^{\circ}[/tex]
