April 22 of the Mystery Year was the first worldwide observance of Earth Day. Skills in this cross-curricular warm-up activity are slope and y-intercept for a line, equation of a line in slope-intercept and standard form, measures of the base angles of an isosceles triangle, point of intersection of two lines, and Pythagorean theorem. Students graph ordered pairs and apply algebraic concepts with those ordered pairs to solve for the Mystery Year.
Your Zip download includes printable/digital PDFs:
- 2-page printable Student Puzzle
- 2-page Answer Key with sample solutions
- 2-page version of puzzle with expanding form fields – use with Acrobat Reader
- A complete file including the student puzzle, answer key, 3 pages of Teacher Notes including step-by-step Solutions, Extensions, and more
- 1-page How to Use History-Mystery Puzzles