What is the arc length of the arc subtended in a circle with radius 6 and an angle of 7pi/8? a) 7pi/4 b) 36pi c) 126pi/4 d) 21pi/4

What is a subtended angle? Well, In geometry a subtended angle is defined as the angle made by a line, arc, object, curve, line segment, etc. It is depending on the context of the problem. In our exercise we are speaking of the angle subtended by an arc of a circumference when the angle's vertex is the center of the circle to which the circumference belongs. That is, we have a circle with the following characteristics:



So the length we need to find is the arc length in red (See the figure below) and we will find out it like this:



Therefore, the correct answer is d)