This site from the University of St. Andrews, gives factual biological information on Cavalieri. Links are provided at the end of the site for more information.

This task applies reflections to a regular hexagon to construct a pattern of six hexagons enclosing a seventh: the focus of the task is on using the properties of reflections to deduce this seven hexagon pattern.

This task applies reflections to a regular octagon to construct a pattern of four octagons enclosing a quadrilateral: the focus of the task is on using the properties of reflections to deduce that the quadrilateral is actually a square.

This book is a "flexed" version of CK-12's Basic Geometry that aligns with College Access Geometry and contains embedded literacy supports. It covers the essentials of geometry for the high school student.

Includes chapters on: Basics of Geometry, Reasoning and Proof, Parallel and Perpendicular Lines, Triangles and Congruence, Relationships with Triangles, Polygons and Quadrilaterals, Similarity, Right Triangle Trigonometry, Circles, Perimeter and Area, Surface Area and Volume, Rigid Transformations.

This Geometry Concept Collection is a rigorous presentation of high school geometry. It is fully correlated with the Common Core State Standards.

CK-12 Middle School Math Concepts for seventh grade provides a complete textbook. It presents topics including algebraic thinking, patterns, decimals, decimal operations, fractions, fraction operations, integers, integer operations, ratios, rates, proportions, percents, percent applications, equations, solving equations, inequalities, functions, graphing functions, geometry, plane geometry, solid geometry, area, perimeter, surface area, volume, statistics including mean, median, mode and range, graphing and types of graphs, and probability.

CK-12 Foundation's Geometry FlexBook is a clear presentation of the essentials of geometry for the high school student. Topics include: Proof, Congruent Triangles, Quadrilaterals, Similarity, Perimeter & Area, Volume, and Transformations.

This FlexBook® resource contains Texas Instruments (TI) Resources for the TI-83, TI-83 Plus, TI-84, and TI-84 SE. All the activities in this resource supplement the lessons in the student edition. Teachers may need to download programs from www.timath.com that will implement or assist in the activities. Each activity included is designed to help the teacher with each activity in the TI Resources FlexBook® Student Edition. All activities are listed in the same order as the Student Edition.

There are also corresponding links in CK-12 Geometry - Second Edition and CK-12 Geometry - Basic.

CK-12 Geometry - Second Edition: https://openspace.infohio.org/courses/geometry-2nd-student-s-edition
CK-12 Geometry - Basic: https://openspace.infohio.org/courses/geometry-basic-student-s-edition

[Free Registration/Login Required] This is a formative assessment task where students are asked to estimate the population of Utah based on information given about its population density and the perimeter of its state boundaries. Samples of student responses and possible misconceptions are provided along with questions to help students clarify their thinking and deepen their understanding.

In this video tutorial, the instructor demonstrates how to determine how to calculate the area of a rectangle and assess knowledge with a quiz. [3:01]

Use different size triangle to determine how to solve for the area in this video lesson. Take quiz to check understanding. [3:41]

In this video tutorial, determine the volume of a rectangular prism and assess learning with a quiz. [4:21]

The purpose of this task is to use geometric and algebraic reasoning to model a real-life scenario. In particular, students are in several places (implicitly or explicitly) to reason as to when making approximations is reasonable and when to round, when to use equalities vs. inequalities, and the choice of units to work with (e.g., mm vs. cm).

At its core, the LEGO MINDSTORMS(TM) NXT product provides a programmable microprocessor. Students use the NXT processor to simulate an experiment involving thousands of uniformly random points placed within a unit square. Using the underlying geometry of the experimental model, as well as the geometric definition of the constant π (pi), students form an empirical ratio of areas to estimate a numerical value of π. Although typically used for numerical integration of irregular shapes, in this activity, students use a Monte Carlo simulation to estimate a common but rather complex analytical form the numerical value of the most famous irrational number, π.

This site from the University of St. Andrews provides biographical information on the mathematician/writer Lewis Carroll, also known as Charles Lutwodge Dodgson.

This University of St. Andrews site contains biographical information and findings of Christiaan Huygens.

This task is primarily about volume and surface area, although it also gives students an early look at converting between measurements in scale models and the real objects they correspond to.

This task shows that the three perpendicular bisectors of the sides of a triangle all meet in a point, using the characterization of the perpendicular bisector of a line segment as the set of points equidistant from the two ends of the segment. The point so constructed is called the circumcenter of the triangle.