You find the circumference and multiply it by the central angle. If the central angle is in degrees, you divide that by 360. If the central angle is in radians, you divide by 2pi.
The graph of the function y = 2x + 7, is a straight line because it is a linear function, and has y-intercept of 7 and a slope of 3; so we are looking for a graph that has these characteristics.
From the 4 graphs, we see that the 1st graph has a slope of 3 and a y intercept of 7, and thus it is the correct answer.