This road sign is on westbound Loop 101 in Phoenix, Arizona.

The road sign says...

+--------------------+ | 56th St 1/4 | | Tatum Blvd 1 1/4 | | 51 South 2 1/4 | +--------------------+the numbers are: 56 (1/4) (1 1/4) 51 (2 1/4) the math is: sqrt(sqrt(2 1/4) - 1 1/4) + sqrt((56 - 51) * 1/4) = Phi observe... sqrt(2 1/4) = sqrt(9/4) = sqrt(9)/sqrt(4) = 3/2 = 1 1/2 1 1/2 - 1 1/4 = 1/4 sqrt(1/4) = sqrt(1)/sqrt(4) = 1/2 56 - 51 = 5 5 * 1/4 = 5/4 sqrt(5/4) = sqrt(5)/sqrt(4) = sqrt(5)/2 1/2 + sqrt(5)/2 = (1 + sqrt(5))/2 Golden ratio = Phi = 1.61803399MathBabbler took the picture used in this BARS on 7 May 2008. He had seen the road sign a few weeks earlier while driving to northwest Phoenix. On this day, MathBabbler sat in on a CSC100 class being held at Notre Dame Preparatory High School located in north Scottsdale. Upon entering the parking lot at the school, he encountered a prime-numbered 5 M.P.H. speed limit sign.

**Creator:** Gerald Thurman
[gthurman@gmail.com]

**Created:** 07 May 2008

This work is licensed under a Creative Commons Attribution 3.0 United States License.