Mathematics Vision Project
Module 6: Congruence, Construction, and Proof
Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This...
Curated OER
Symmetries of Rectangles
Learners explore mapping a rectangle onto itself using rigid motion concepts, geometric intuition and experimenting with manipulatives in a collaborative task.
Curated OER
Symmetries of a Quadrilateral II
Learners investigate the symmetries of a convex quadrilateral in a collaborative activity. Rigid motion and complements are explored as learners analyze different cases of reflections across a line.
Curated OER
Symmetries of a Quadrilateral I
Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...
Curated OER
Seven Circles II
Your learners find as many rigid motions of the plane as they can that are symmetries of the configuration of circles. Rigid transformations of the plane are explored and become more concrete to them as they visualize and execute...
Curated OER
Reflections and Equilateral Triangles II
Given the lines of symmetry in an equilateral triangle, your learners find where the pre-image vertices are mapped onto the new image. They explore the properties of equilateral triangles, the impact of reflections, and the...
Curated OER
Reflections and Equilateral Triangles
Your learners collaboratively find the lines of symmetry in an equilateral triangle using rigid transformations and symmetry. Through congruence proofs they show that they understand congruence in terms of rigid motions as they...
Curated OER
Unit Squares and Triangles
This is an interesting geometry problem. Given the figure, find the area of a triangle that is created by the intersecting lines. The solution requires one to use what he/she knows about coordinate geometry, as well as triangle...
Kuta Software
Reflections of Shapes
In this reflection of shapes worksheet, learners graph images on a coordinate plane. They reflect the image and sketch it on the graph. They write a rule to describe the transformation. This four-page worksheet contains 14 problems....
Curated OER
Conics in Geometry
High schoolers analyze characteristics and properties of two and three-dimensional shapes in this geometry lesson. They follow detailed directions to use the Cabri Geometry II Application on their TI-89 calculator to construct a...
Curated OER
What's the Spin?
Learners use the CABRI application for their graphing calculator to rotate, translate, and reflect triangles. They use graphing calculators and follow detailed directions to manipulate triangles in specified ways. There are three...
Curated OER
Using Symmetry to Find the Vertex of a Parabola
Learners engage in a lesson that is about finding the vertex of a parabola while using symmetry. They use the symmetry to find out where the two lines meet. The line is displayed with the help of a graphing calculator. The lesson...
Maths Challenge
Maths challenge.net: Triangle Area
Find the area of this triangle in a coordinate plane.
Maths Challenge
Maths challenge.net: Isosceles Trapezium
This is a "three star" geometry problem where prior knowledge of problem solving and thinking through proofs is recommended to solve this trapezoid inscribed in a semicircle problem.
Texas Education Agency
Texas Gateway: Making Conjectures About Quadrilaterals
Given examples of quadrilaterals and their component parts, the student will use explorations and concrete models to prove a quadrilateral is a parallelogram, rectangle, square, or rhombus using opposite sides, opposite angles, or...
Mathigon
Mathigon: Geometry: Polygons and Polyhedra: Polygons
This lesson focuses on polygons; a polygon is a closed, flat shape that has only straight sides. Polygons can have any number of sides and angles, but the sides cannot be curved.
Cuemath
Cuemath: Equilateral
Learn all about the basic properties of equilateral. This lesson targets the meaning of equilateral, shows how to construct equilateral shapes, explores some of the equilateral shapes and properties, and how to apply them while solving...
Math.com
Math.com: Quadrilaterals
The lesson investigates types of quadrilaterals. Definitions, examples, and a worksheet are available.
University of Illinois
University of Illinois Urbana Champaign: The Geometry Center: Area of Quadrilaterals
Formulas on calculating the area of a general quadrilateral and special cases of quadrilaterals.
Wolfram Research
Wolfram Math World: Squares
MathWorld provides multiple definitions and formulas for the mathematical term, square.
Texas Instruments
Texas Instruments: Isosceles Triangle
In this activity, students construct isosceles and equilateral triangles. They discover that if two sides of a triangle are congruent, then the angles opposite them are congruent. They understand that an equilateral triangle is also...
Texas Instruments
Texas Instruments: Cyclic Quadrilaterals
Students construct cyclic quadrilaterals and investigate their properties. They determine which quadrilaterals from the quadrilateral hierarchy are cyclic.
Texas Instruments
Texas Instruments: What Quadrilateral Is It?
Students will algebraically determine what type of quadrilateral that is pictured in the activity center.
Texas Instruments
Texas Instruments: Angle Bisectors and Medians of Quadrilaterals
In this activity, students will construct angle bisectors and medians in quadrilaterals and explore the properties that appear to be true for four-sided figures. They may find it necessary to review the definitions and properties of...