ALEX Lesson Plans Subject: Mathematics (9 - 12) Title: Construct This! Description: Students will construct equilateral triangles, squares, and regular hexagons inscribed in circles using the free GeoGebra computer program. Thinkfinity Lesson Plans Subject: MathematicsTitle: IGD: Simson Line      Add Bookmark Description: This student interactive, from Illuminations, helps students understand and investigate a triangle s Simson line, which is the line passing through the feet of the perpendiculars dropped from P to the three sides of a triangle. Students construct the Simson line for a given triangle using the interactive applet.Thinkfinity Partner: IlluminationsGrade Span: 9,10,11,12Subject: MathematicsTitle: Triangle Classification      Add Bookmark Description: This student interactive, from an Illuminations lesson, allows students to turn a segment into a right triangle, an isosceles triangle, and an obtuse triangle.Thinkfinity Partner: IlluminationsGrade Span: 9,10,11,12Subject: MathematicsTitle: All in the Family       Add Bookmark Description: In this Illuminations lesson, students use a dynamic geometry applet to conjecture about the relationships between characteristics of a square: side length, diagonal length, perimeter, and area. Students use graphs to represent functional relationships between two characteristics, such as diagonal length as a function of perimeter. In addition, there are links to online activities, reproducibles, and other related resources.Thinkfinity Partner: IlluminationsGrade Span: 9,10,11,12