MINI #43 - USING SIMILARITY TO SOLVE GEOMETRY PROBLEMS Plane Geometry Proportional Reasoning Solid Geometry Video by Art of Problem Solving's Richard Rusczyk. Read More
VALENTINE'S DAY TREATS Probability, Counting and Combinatorics Proportional Reasoning Sequences, Series and Patterns According to “A History of Valentine’s Day Cards in America” by T.M. Wilson, in 1847 Esther Howland was the first to mass-produce Valentine’s Day cards. She made them out of lace, paint and expensive... Read More