Instructional Video
Khan Academy

Khan Academy: Geometry: Proof Sum of Measures of Angles in a Triangle Are 180

For Students 9th - 10th
Proof that the sum of the angles in a triangle is 180 using the relationship of angles formed when parallel lines are cut by a transversal. This video also appears in the Geometry: Triangles strand. [6:31]
Instructional Video
Khan Academy

Khan Academy: Ca Geometry: Basic Trigonometry

For Students 9th - 10th Standards
Demonstrates solutions to problems #61-65 of California Geometry released state test questions. Problems address the equation of a circle, basic trigonometry. [11:04]
Instructional Video
Khan Academy

Khan Academy: Geometry: Right Triangles Inscribed in Circles (Proof)

For Students 9th - 10th Standards
This video tutorial [5:35] explains that if the diameter of a circle is one of the sides of a triangle inscribed in the circle then the triangle is a right triangle. This video also appears in the strand Geometry: Circles.
Instructional Video
Khan Academy

Khan Academy: Geometry: Problem Involving Angle Derived From Square and Circle

For Students 9th - 10th Standards
Demonstrates how to solve a challenging geometry problem about finding the measure of an angle that is formed by different segments in a square which intersect with part of a circle. Solution depends on creating triangles in the diagram...
Instructional Video
Khan Academy

Khan Academy: Geometry: Inradius Perimeter and Area

For Students 9th - 10th Standards
Proof that the area of a triangle is equal to half the inradius times the perimeter of the triangle, or the area is equal to the inradius times the semiperimeter. This video also appears in the Geometry: Circles strand. [7:29]
Instructional Video
Khan Academy

Khan Academy: Geometry: More on Why Ssa Is Not a Postulate

For Students 9th - 10th Standards
Explains why SSA is not a valid postulate for proving triangle congruence. Practice problems available. This video [7:24] also appears in the Geometry: Triangles strand.
Instructional Video
Khan Academy

Khan Academy: Geometry: Triangle Angle Example 3

For Students 9th - 10th
Explains how to solve for multiple missing angles in a diagram composed of multiple triangles using the triangle sum theorem and other angle relationships. This video also appears in the Geometry: Triangles strand. [5:42]
Instructional Video
Khan Academy

Khan Academy: Geometry: 2003 Aime Ii Problem 7

For Students 9th - 10th
Explanation of 2003 AIME II (American Invitational Mathematics Examination) Problem 7. Finding the area of a rhombus based on the circumradii of triangles. This video also appears in the Geometry: Polygons, quadrilaterals, and...
Instructional Video
Loyola University Chicago

Math Flix: Extended Response: Area Rectangle Explanation

For Students 3rd - 8th
This video [6:10] works through a geometry problem using area and perimeter. This real world problem will require an extended response. The teacher and student discuss how to work through it together to find the solution. As you watch...
Instructional Video
Other

Math Counts Foundation: Probability With Geometry Representations

For Students 9th - 10th Standards
This video focuses on probability with geometry representations. Links to an activity sheet and the solutions also available.
Instructional Video
Loyola University Chicago

Math Flix: Extended Response: Make Rectangle Solution 2

For Students 3rd - 8th
This QuickTime movie continues working through a geometry problem using area and perimeter. This real world problem will require an extended response. The teacher and student discuss how to work through it together to find the solution....
Instructional Video
Loyola University Chicago

Math Flix: Extended Response: Make Rectangle Solution 1

For Students 3rd - 8th
This QuickTime movie works through a geometry problem using area and perimeter. This real world problem will require an extended response. The teacher and student discuss how to work through it together to find the solution. As you watch...
Instructional Video
Loyola University Chicago

Math Flix: Extended Response: Make Rectangle Explanation

For Students 3rd - 8th
This QuickTime movie continues working through a geometry problem using area and perimeter. This real world problem will require an extended response. The teacher and student discuss how to work through it together to find the solution....
Instructional Video
Khan Academy

Khan Academy: Euclid as the Father of Geometry

For Students 6th - 8th
Euclid was a great mathematician and often called the father of geometry. Learn more about Euclid and how some of our math concepts came about and how influential they have become.
Instructional Video
Loyola University Chicago

Math Flix: Extended Response: Area Rectangles Solution

For Students 3rd - 8th
This video [3:23] works through a geometry problem using area and perimeter. This problem, in the form of a riddle, will require an extended response. As you watch and listen to the teacher and student interact it helps clarify the...
Instructional Video
Khan Academy

Khan Academy: Geometry: Similar Triangles

For Students 9th - 10th Standards
Explains what it means for two triangles to be similar. Diagram of similar triangles is created with two parallel lines cut by two transversals. [9:34]
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Reflective Symmetry

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video tutorial on line or reflective symmetry.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview Sum of the Angles of a Triangle

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on funding the sum of angles in a triangle.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Area

For Students 2nd - 4th
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on area.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Basic 3 D Figures

For Students 2nd - 4th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on the properties of three dimensional figures.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Rectangles Squares Circles and Triangles

For Students 2nd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on various two dimensional shapes including rectangles, squares, circles and triangles.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Area and Perimeter

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on the area and perimeter of squares and rectangles.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Area and Perimeter of Rectangle

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on how to find the area and perimeter of a rectangle.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Area and Perimeter of Squares

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on how to find the area and perimeter of squares.

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