# Throwing Pi

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In this calculus activity, learners use a classic problem of geometrical probability to find an important mathematical constant (pi). Learners explore Buffonäóťs needle problem (which asks the probability of a needle hitting a line if it is thrown at a group of evenly spaced parallel lines) by physically throwing toothpicks and graphing the results.

Material Type: Activity/Lab

# Finding Equations of Parallel and Perpendicular Lines

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This lesson unit is intended to help teachers assess how well students are able to understand the relationship between the slopes of parallel and perpendicular lines and, in particular, to help identify students who find it difficult to: find, from their equations, lines that are parallel and perpendicular; and identify and use intercepts. It also aims to encourage discussion on some common misconceptions about equations of lines.

Material Type: Assessment, Lesson Plan

# Find the Missing Angle

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This task "Uses facts about supplementary, complementary, vertical, and adjacent angles in a multi-step problem to write and solve simple equations for an unknown angle in a figure (7.G.5)" except that it requires students to know, in addition, something about parallel lines, which students will not see until 8th grade.

Material Type: Activity/Lab

Author: Illustrative Mathematics

# Perpendicular lines. (Coordinate Geometry)

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An interactive applet and associated web page that show how to determine of one line is perpendicular to another in coordinate geometry. The principle used is that if two lines a re perpendicular to each other the slope of one is the negative reciprocal of the other. The applet shows to lines that the user can move. The slopes are continuously calculated as you drag them, and if the they are parallel they change color. The calculation is shown on screen updated continuously as you drag. The grid, axis pointers and coordinates can be turned on and off. The calculation display can be turned off to permit class exercises and then turned back on the verify the answers. The applet can be printed as it appears on the screen to make handouts. The web page has a full description of the concept of perpendicularity, a worked example and has links to other pages relating to coordinate geometry. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Author: John Page

# Math, Grade 7, Proportional Relationships, Gallery Problems Exercise

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Allow students who have a clear understanding of the content thus far in the unit to work on Gallery problems of their choosing. You can then use this time to provide additional help to students who need review of the unit's concepts or to assist students who may have fallen behind on work.Gallery DescriptionSolving Percent ProblemsStudents understand the structure of percent problems by analyzing many problems.Running a Clothing StoreStudents help the owner of a clothing store determine how to get the greatest profit.Less FatStudents determine the percentage of fat in whole milk.10% MoreStudents evaluate three statements from Huey, Dewey, and Louie and determine which statement is correct.Free SpaceStudents determine which of two hard drives has the most free space.

Material Type: Lesson Plan

# Walk the Line: A Module on Linear Functions

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