Curated OER
Find the Hidden Shapes
What shape do I see? Pupils will use what they know about geometric figures to determine which shape is hidden behind the squares. The shapes identified in the game: square, triangle, hexagon, and decagon. This is a great warm-up activity.
Curated OER
Circles
In this circles learning exercise, 10th graders solve and complete 20 different problems related to various circles. First, they find the radius and diameter of a circle with a given circumference. Then, students determine the measure of...
Curated OER
Polygon Mobiles
Students explore a variety of shapes and angles and create mobiles with information about a selected polygon. Both common and "not-so common" polygons are examined.
University of Georgia
University of Georgia: Inter Math: Decagon
Intermath offers a definition of a decagon with a drawing of one. The site contains links to the left that give a real world example, related terms, an understanding of the term, "Interactive Checkpoint", and challenging problems related...
The Math League
The Math League: Figures and Polygons
This site provides definitions of different types of polygons and figures.
Math Open Reference
Math Open Reference: Decagon (10 Gon)
Learn about decagons with this resource which offers detailed explanations, examples, and an interactive. Subjects covered include properties of decagons. Links to related topics.
The Math League
The Math League: Figures and Polygons
This website has basic definitions for most polygons, regular and irregular.
National Council of Teachers of Mathematics
The Math Forum: Problems Library Geometry Triangles
This site contains a wealth of problems that deal with the basic definitions of medians, altitudes, angle bisectors, and perpendicular bisectors or the defining characteristics of the different types of triangles. There are also...
Calculator Soup
Calculator Soup: Regular Polygon Calculator
Use this calculator to calculate properties of a regular polygon. Enter any 1 variable plus the number of sides or the polygon name. Calculates side length, inradius, circumradius, area, and perimeter.