Interactive
Mangahigh

Mangahigh: Shape: Congruent Triangles

For Students 9th - 10th Standards
Explain how two triangles are congruent.
Interactive
Mangahigh

Mangahigh: Shape: Isosceles Triangles Inside Circles

For Students 9th - 10th Standards
Determine isosceles triangles inside a circle made from chords and radii.
Interactive
Mangahigh

Mangahigh: Shape: Right Angle in a Semi Circle Rule

For Students 6th - 9th Standards
Test your knowledge of the measurement of angles in a triangle.
Handout
Varsity Tutors

Varsity Tutors: Hotmath: Algebra Review: Quadrilaterals

For Students 9th - 10th Standards
Find a quick, concise explanation of a quadrilateral. Examples are given and clearly explained.
Unit Plan
CK-12 Foundation

Ck 12: Geometry: Parallelograms

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This concept teaches students properties of and theorems about parallelograms and how to apply them.
Interactive
CK-12 Foundation

Ck 12: Isosceles Triangles

For Students 7th - 9th Standards
[Free Registration/Login Required] Students are given an Isosceles triangle and are asked to move the point on the line segment to explore how the angle measure changes. Click learn more to watch a video demonstration and click challenge...
Interactive
CK-12 Foundation

Ck 12: Equilateral Triangles

For Students 7th - 9th Standards
[Free Registration/Login Required] Students will move point B on the triangle to explore that all sides and angles remain the same. Click learn more to watch a video and click challenge me to answer a practice question.
Activity
CK-12 Foundation

Ck 12: Parallelograms

For Students 9th - 10th Standards
[Free Registration/Login Required] Students will move the points on the parallelogram to explore what happens to the slope. Click learn more to watch a video and click challenge me to answer a practice question.
Activity
Analyze Math

Analyze Math: Medians of Triangle

For Students 9th - 10th Standards
The properties of the medians of a triangle are explored using an interactive geometry applet.
Activity
Texas Instruments

Texas Instruments: Properties of Parallelograms

For Teachers 9th - 10th Standards
This activity shows the student how to construct a parallelogram using Cabri Geometry. Questions are asked after the construction.
Activity
Texas Instruments

Texas Instruments: Properties of Parallelograms

For Teachers 9th - 10th Standards
In this activity, students go through the process of proving a quadrilateral to be a parallelogram. They understand the various characteristics of a parallelogram.
Activity
Texas Instruments

Texas Instruments: Properties of Parallelograms

For Teachers 9th - 10th Standards
In this activity, you will construct the geometric object by following the instructions below, and then answer the questions about the object.
Activity
Texas Instruments

Texas Instruments: Rotations in the Plane

For Teachers 9th - 10th Standards
In this activity, students will explore the properties of rotations and the relationships between the original and image figures.
Handout
Free Math Help

Free Math Help: Geometry: Parallelograms: What Is a Parallelogram?

For Students 9th - 10th Standards
The lesson discusses parallelograms. The resource examines facts, diagonals, and sides of a parallelogram. Explanations and examples are included.
Activity
Analyze Math

Analyze Math: Rhombus Problems

For Students 9th - 10th Standards
The geometry tutorial explores the definition, area, and properties of a rhombus. The activity has several examples with detailed solutions.
eBook
Math Planet

Math Planet: Pre Algebra: Triangles

For Students 9th - 10th Standards
Learn about the types of triangles by taking a look at an example and a video lesson.
eBook
Math Planet

Math Planet: Geometry: Parallelogram, Triangles Etc

For Students 9th - 10th Standards
Resource examines the area of geometric solids through examples and a video lesson. [0:39]
eBook
Mathigon

Mathigon: Geometry: Polygons and Polyhedra: Quadrilaterals

For Students 9th - 10th Standards
This lesson focuses on quadrilaterals which can fall into multiple categories based on the number of sides and the angles.
eBook
Mathigon

Mathigon: Geometry: Polygons and Polyhedra: Polyhedra

For Students 9th - 10th Standards
This lesson focuses on polyhedra; a polyhedron (the plural is polyhedra) is a 3-dimensional solid object that is made up of polygons. Euler's Polyhedron Formula: In every polyhedron, the number of faces (F) plus the number of vertices...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Origami Regular Octagon

For Teachers 9th - 10th Standards
After successive folds of a piece of origami paper, a student must explain why the shape made is a regular octagon. Aligns with G-CO.A.3 and G-CO.D.12.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Seven Circles Ii

For Teachers 9th - 10th Standards
In this task, seven pennies are placed in a circle so that they are all touching one in the center and their neighbors. Students are asked to find as many rigid motions of the plane as they can which are symmetries of this configuration...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Symmetries of a Quadrilateral I

For Teachers 9th - 10th Standards
Suppose ABCD is a quadrilateral for which there is exactly one rotation, through an angle larger than 0 degrees and less than 360 degrees, which maps it to itself. Further, no reflections map ABCD to itself. What shape is ABCD? Aligns...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Symmetries of a Quadrilateral Ii

For Teachers 9th - 10th Standards
There is exactly one reflection and no rotation that sends the convex quadrilateral ABCD onto itself. What shape(s) could quadrilateral ABCD be? Explain. Aligns with G-CO.A.3.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Symmetries of Rectangles

For Teachers 9th - 10th Standards
This task examines the rigid motions which map a rectangle onto itself. The emphasis here is on careful reasoning using the definitions of reflections and rotations. Aligns with G-CO.A.3.