If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

## Geometry (all content)

### Course: Geometry (all content)>Unit 14

Lesson 5: Arc length (from radians)

# Challenge problems: Arc length (radians) 2

Solve two challenging problems that ask you to find an arc measure using the arc length.

## Problem 1

In the figure below, start overline, A, C, end overline is a diameter of circle P. The radius of circle P is 30 units. The arc length of B, C, start superscript, \frown, end superscript is 13, pi.
A circle that is centered around point P. Points A, B, and C are on the circle and line segment A C is a diameter. Line segments A P, B P and C P are radii of the circle that are thirty units long. Minor arc B C is thirteen pi units long.
What is the arc measure of A, B, start superscript, \frown, end superscript, in radians?