# What is the distance between the following polar coordinates?:  (1,(7pi)/12), (3,(9pi)/8)

$d \approx 3.28$
$d = \sqrt{{r}_{1}^{2} - 2 {r}_{1} {r}_{2} \cos \left({\theta}_{1} - {\theta}_{2}\right) + {r}_{2}^{2}}$
d=sqrt(1^2-2(1)(3)cos((7pi)/12 -(9pi)/8)+3^2
$d \approx 3.28$