A circle's center is at (3,5) and it passes through (2,8). What is the length of an arc covering 5π4 radians on the circle?

1 Answer
Nov 22, 2016

510π4

Explanation:

Part 1
If a circle has a center at (3,5) and passes through (2,8)
it has a radius of r=(32)2+(58)2=1+9=10

Part 2
An arc with an angle of k radians
has a length of k2π×circumference of the circle
but since the circumference of the circle=2πr
the length of an arc with an angle of k radians is k * r#

Part 3
For the given circle and arc
the arc length is 5π4×10