[Free Registration/Login may be required to access all resource tools.] Learn about the Inscribed Quadrilateral Theorem and solve problems involving quadrilaterals inscribed in circles.

Explore and measure a variety of quadrilaterals.

Quadrilaterals-parallelograms, rectangles, and trapezoids-are thoroughly introduced in this lesson plan for upper elementary and middle school students. Lots of resources are linked to it to help support the teacher and students....

In this task, learners analyze the characteristics of a right triangle that has two sides labeled with midpoints and show that the triangle is inscribed in a circle with a diameter the length of its hypotenuse. Aligns with G-C.A.2.

This task provides a good opportunity to use isosceles triangles and their properties to show an interesting and important result about triangles inscribed in a circle with one side of the triangle a diameter. The fact that these...

The students will explore angles, rays, line segments, perpendicular lines, parallel lines, and two-dimensional figures through the use of the book Shape Up! Fun With Triangles and Other Polygons by David A. Adler. They will also...

This activity is used to discover that the sum of the measures of the triangle angles is constant and to discover ways of proving the theorem listed in the activity.

[Free Registration/Login may be required to access all resource tools.] Students watch a video tutorial and attempt practice problems on identifying the properties of rectangles.

[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on identifying the properties of squares.

Students reflect on their work and apply what they've learned about the characteristics of geometric figures. Includes a learning game to be played with a partner.

[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...

[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.

The Chinese character mark for Tan II (pronounced she-tow-bah) is the second of two lessons to introduce first grade students to geometry using tangrams. This lesson incorporates history, math, and language arts. In this lesson students...

[Free Registration/Login Required] Learn about polygons, angles, parallel, intersecting and perpendicular lines as you journey into space. Included is an activote quiz.

[Free Registration/Login Required] With this flipchart students will learn how to classify two-dimensional shapes and discuss the attributes of polygons.

This picture shows an equilateral triangle, a three sided regular polygon with internal angles of 60 degrees and sides of equal length.