A circle is inscribed in an isosceles trapezoid. Find the relationship of the radius to the sides.

- About MAA
- Membership
- MAA Publications
- Periodicals
- Blogs
- MAA Book Series
- MAA Press (an imprint of the AMS)
- MAA Notes
- MAA Reviews
- Mathematical Communication
- Information for Libraries
- Author Resources
- Advertise with MAA

- Meetings
- Competitions
- Programs
- Communities
- MAA Sections
- SIGMAA
- MAA Connect
- Students
- MAA Awards
- Awards Booklets
- Writing Awards
- Teaching Awards
- Service Awards
- Research Awards
- Lecture Awards
- Putnam Competition Individual and Team Winners
- D. E. Shaw Group AMC 8 Awards & Certificates
- Maryam Mirzakhani AMC 10 A Awards & Certificates
- Two Sigma AMC 10 B Awards & Certificates
- Jane Street AMC 12 A Awards & Certificates
- Akamai AMC 12 B Awards & Certificates

- High School Teachers

- News