Practice finding the area of right, acute, and obtuse triangles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

In this task, students 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...

Students solve for missing angle measures by applying what they have learned about types of angles and the angle measures of polygons. Students do a pre-assessment at the end of the lesson.

In Spanish. Interactive activities dealing with the definition, angles and area of a polygon.

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 lesson is a unique and fun way to review perimeter, angles, and types of adjectives. Students pick an object from the classroom that will fit in a paper lunch bag. They investigate their object and fill in the attached sheet. You...

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...

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.