ALEX Lesson Plans Subject: Mathematics (9 - 12) Title: PER - PIN - TIC - YOU - LER! (Part 2 to Take the Stairs Lesson) Description: This lesson allows students to investigate the slope criteria and characteristics of perpendicular lines using graphing calculators and rectangle/square tiles.  Students will also use equations and graphs.  Students will work cooperatively to develop and justify ideas/conjectures. This is a College- and Career-Ready Standards showcase lesson plan.Subject: Mathematics (9 - 12) Title: Take the Stairs to Slope! Description: This lesson allows students to investigate the slope criteria and characteristics of parallel lines using graphing calculators and school staircases.  Students will also use equations and graphs.  Students will work cooperatively to develop and justify ideas/conjectures. This is a College- and Career-Ready Standards showcase lesson plan.Subject: Mathematics (9 - 12) Title: What do we have in Common?  Discover the properties of the diagonals of quadrilaterals. Description: This inquiry lesson explores the definitions of quadrilaterals and the properties of the diagonals of quadrilaterals to classify quadrilaterals. Students will work cooperatively to justify conclusions. This lesson plan was created by exemplary Alabama Math Teachers through the AMSTI project.Subject: Mathematics (8 - 12) Title: Quadrilaterals Description: This is an inquiry lesson used to review Algebra 1 objectives by applying them to geometry concepts. Students explore the properties of quadrilaterals and classify them by definition. This lesson can be use in geometry classes. Students in geometry classes can apply theorems and definitions of quadrilaterals rather than as an inquiry lesson.This lesson plan was created as a result of the Girls Engaged in Math and Science, GEMS Project funded by the Malone Family Foundation.Subject: Mathematics (8 - 12) Title: What is the slope of the stairs in front of the school? Description: The purpose of this lesson is to help students apply the mathematical definition of slope to a concrete example. The students will learn to make the appropriate measurements and apply the formula to calculate the slope of the stairs experimentally. Thinkfinity Lesson Plans