How to find theta in area of sector?

When it comes to calculating the area of a sector in a circle, theta - the angle of the sector - plays a crucial role. But how do we determine theta accurately? Is it measured in degrees or radians? What methods should we use to measure or calculate theta? Do we need to consider the arc length or other properties of the sector? Understanding theta's role in determining the area of a sector is essential for accurate calculations. Could you elaborate on how theta is determined and its importance in sector area calculations?