A circle's center is at (3 ,1 )(3,1) and it passes through (4 ,2 )(4,2). What is the length of an arc covering ( pi ) /6 π6 radians on the circle?

1 Answer
Feb 4, 2016

(pisqrt(2))/6π26

Explanation:

The circle equation is (x-h)^2 +(y-k)^2 = r^2(xh)2+(yk)2=r2 where (h,k)(h,k) is the centre and rr is the radius. We can find rr by substituting in the coordinates of the given point.

(4-3)^2 +(2-1)^2 = r^2(43)2+(21)2=r2

1^2 +1^2 = r^212+12=r2

:. r= sqrt(2)

The complete circle subtends an angle of 2pi (360^o) so the arc subtending pi/6 represents (pi/6)/(2pi) of the circumference which is 1/12

Arc length = 1/12*(2pir) = 2pisqrt(2)/12 =(pisqrt(2))/6