## Girls’ Angle Bulletin, Volume 15, Number 5

In this issue, we’re thrilled to present our interview with mathematician Zoi Rapti, a professor in the mathematics department at the University of Illinois, Urbana-Champaign. Prof. Rapti is the 60th woman in mathematics who we’ve had the pleasure of interviewing. One of the reasons we’re excited about our interview with Prof. Rapti is that she is also a professor at the Carl R. Woese Institute for Genomic Biology, and we know that many of our members are interested in studying biology as well as mathematics. One of the applications of math that Prof. Rapti discusses is in analyzing the color patterns of bees.

Next, Robert Donley continues to develop his exposition on counting, turning now to the Catalan numbers. Did you know that the entry for the Catalan numbers on the On-Line Encyclopedia of Integer Sequences is longer than the corresponding entry for the Fibonacci numbers (as of this writing)?

In her latest installment of Needell in the Haystack, Anna Ma discusses data visualization – ways to present data in a way that helps humans to understand the data. This is an important, active topic.

Next, we present this summer’s batch of Summer Fun problem sets. There are three, and the third includes a special raffle contest for a chance to win a modest prize. The first, by Laura Pierson, connects labeled trees to parking functions. The second, by Mandy Cheung, is a modification on the water bucket genre of puzzle to the task of making orange juice. And the third, by AnaMaria Perez and Josh Josephy-Zack, represents a bit of an exception to our standard fare of mathematics. The two present a series of Fermi questions – questions that are either impractical or impossible to answer exactly, so you have to give your best estimate. Most of these questions will involve having some general world knowledge. At the end of their problem set, you’ll find two bonus questions and whoever (within the United States) submits the best estimate will receive a choice of chocolate or a math book.

We conclude with Notes from the Club, presenting three problems from an amazing Math Collaboration that was created by four of our members – a first at Girls’ Angle!

We hope you enjoy it!

Finally, a reminder: when you subscribe to the Girls’ Angle Bulletin, you’re not just getting a subscription to a magazine. You are also gaining access to the Girls’ Angle mentors.  We urge all subscribers and members to write us with your math questions or anything else in the Bulletin or having to do with mathematics in general. We will respond. We want you to get active and do mathematics. Parts of the Bulletin are written to induce you to wonder and respond with more questions. Don’t let those questions fade away and become forgotten. Send them to us!

Also, the Girls’ Angle Bulletin is a venue for students who wish to showcase their mathematical achievements that go above and beyond the curriculum. If you’re a student and have discovered something nifty in math, considering submitting it to the Bulletin.

We continue to encourage people to subscribe to our print version, so we have removed some content from the electronic version.  Subscriptions are a great way to support Girls’ Angle while getting something concrete back in return.  We hope you subscribe!