# A circle has a center at (1 ,3 ) and passes through (2 ,4 ). What is the length of an arc covering pi /4  radians on the circle?

Oct 2, 2016

$s = \frac{\sqrt{2} \pi}{4}$

#### Explanation:

r² = (2 - 1)² + (4 - 3)²
$r = \sqrt{2}$
$s = r \theta$
$s = \frac{\sqrt{2} \pi}{4}$