Math Planet
Math Planet: Geometry: Polygons
A definition, examples, and a video lesson all help to explain polygons. [0:43]
Math Planet
Math Planet: Geometry: More About Triangles
Explores triangles and related vocabulary through examples and a video lesson.
Illustrative Mathematics
Illustrative Mathematics: G Co Inscribing a Square in a Circle
In this lesson, students learn how to inscribe a square in a circle. Aligns with G-CO.D.13
Mangahigh
Mangahigh: Shape: Proof of the Sum of the Angles in a Triangle
Determine that all angles in a triangle equal 180 degrees.
Mangahigh
Mangahigh: Shape: Recognize Quadrilaterals
Determine quadrilaterals based on parallel sides.
Mangahigh
Mangahigh: Shape: Area of a Triangle Using Trigonometry
Teat your knowledge of determing the area of a triangle using trigonometry.
Mangahigh
Mangahigh: Shape: Isosceles Triangles Inside Circles
Determine isosceles triangles inside a circle made from chords and radii.
Mangahigh
Mangahigh: Shape: Right Angle in a Semi Circle Rule
Test your knowledge of the measurement of angles in a triangle.
Mangahigh
Mangahigh: Shape: Quadrilaterals Inscribed in Circles
Determine the missing angle measures of quadrilaterals inscribed in circles.
Mangahigh
Mangahigh: Shape: 3 D Trigonometry
Test your knowledge of determing the lengths and angles of right triangles.
CK-12 Foundation
Ck 12: Geometry: Equilateral Triangles
[Free Registration/Login may be required to access all resource tools.] In this lesson students apply the properties of equilateral triangles. Students examine guided notes, review guided practice, watch instructional videos and attempt...
CK-12 Foundation
Ck 12: Geometry: Equilateral Triangles
[Free Registration/Login may be required to access all resource tools.] This concept will teach students the properties of equilateral triangles and how to apply them to solve problems. Students examine guided notes, review guided...
CK-12 Foundation
Ck 12: Isosceles Triangles
[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...
CK-12 Foundation
Ck 12: Equilateral Triangles
[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.
Texas Instruments
Texas Instruments: Areas of Regular Polygons and Circles
Use Cabri Jr. to find the area of several regular polygons and then use that investigation to derive the area of a circle from a many-sided polygon.
Analyze Math
Analyze Math: Polygons Problems
Here are four problems about the area of a regular polygon. Start by finding the area of a hexagon inscribed in a circle of radius 10, and end by proving that as the number of sides of the polygon increases, the area of the polygon...
Wolfram Research
Wolfram Math World: Equilateral Triangle
MathWorld goes into detail about equilateral triangles at this site. Use this site to find out how to construct an equilateral triangle using a compass and straight edge. Learn about the altitude of such triangles, and the rationality of...
Depaul University
Depaul University: Inscribing Regular Polygons
In this lesson, students learn to inscribe regular polygons inside a circle.
CK-12 Foundation
Ck 12: Area and Perimeter of Triangles
[Free Registration/Login Required] Students are given the base and height of a triangle and are to determine the area and perimeter. Click challenge me to answer practice questions and click learn more to watch a video.
Analyze Math
Analyze Math: Regular Polygons
The interactive tutorial examines the properties and formulas of regular polygons, inscribed circles, and circumscribed circles.
Analyze Math
Analyze Math: Area of Triangles
The geometry resource explores the different formulas used to calculate the area of triangles. The applet investigates the angles and sides of a triangle.
University of California
University of California: Triangles and Simplices
This site from the University of California deals with different applications and topics pertaining to triangles, particularly triangulation.