A circle has a center at (7,9) and passes through (1,1). What is the length of an arc covering 3π4 radians on the circle?

1 Answer
Feb 3, 2016

15π2

Explanation:

First thing to do is to find the length of the radius. The line segment joining the center of the circle to any point on the circle constitutes a radius.

Therefore, the line segment joining (7,9) and (1,1) is a radius. To find its length, you can use Pythagoras Theorem.

r=(71)2+(91)2=10

Next, you should know that an arc subtending an angle of θ in radians, has arc length, s, given by s=rθ.

s=(10)(3π4)=15π2