A circle has a center at #(7 ,6 )# and passes through #(2 ,1 )#. What is the length of an arc covering #pi/8# radians on the circle?
We know the center and a point on the circle. The distance between the two points is the radius (draw a picture and convince yourself this).
We know that the distance between two points
By definition, a radian is the angle subtended by an arc of length equal to the radius. Thus, an arc which subtends an angle of
Hint to remember
Note that the circumference subtends and angle of