Instructional Video
Khan Academy

Khan Academy: Weighted Average of Two Points

For Students 9th - 10th
This video [3:56] lesson focuses on how to bridge two worlds: the world of images and geometry and the world of algebra, numbers, and equations. We will develop a formula that will allow us to compute points exactly on the parabola. And...
Instructional Video
Sophia Learning

Sophia: Calculating the Area of a Triangle

For Students 6th - 8th Standards
Use different size triangle to determine how to solve for the area in this video lesson. Take quiz to check understanding. [3:41]
Instructional Video
Sophia Learning

Sophia: Calculating the Surface Area of a Cylinder

For Students 9th - 10th
In this video lesson, students will determine how to find the surface area of a cylinder and assess learing with a quiz. [4:02]
Instructional Video
Sophia Learning

Sophia: Finding a Formula for the Volume of a Cylinder

For Students 9th - 10th
This video lesson students how to determine the volume of a cylinder and check understanding with a quiz. [2:21]
Instructional Video
Sophia Learning

Sophia: Finding the Surface Area of a Cylinder

For Students 9th - 10th
In this video lesson, students will determine the surface area of a cylinder using perimeter, area and circles. Take a quiz to assess learning. [3:47]
Instructional Video
Sophia Learning

Sophia: Finding Unknown Angles From Supplementary Angles

For Students 9th - 10th
Explore supplementary angles and how to find the unknown angle in this video lesson. [2:45] Take a quiz to assess learning.
Instructional Video
Sophia Learning

Sophia: Graphing Reflections

For Students 9th - 10th Standards
In this video tutorial lesson, the term "reflection" is defined and examples are given to show a reflection when graphing. [3:22] Take assessment to check understanding.
Instructional Video
Sophia Learning

Sophia: Interior and Exterior Angles of Polygons

For Students 9th - 10th
Interior and exterior angles of polygons are investigated in this geometry resource. Definitions and video lessons are included.
Instructional Video
Sophia Learning

Sophia: Intersecting Planes and the Coordinate Plane

For Students 9th - 10th
In this video lesson, students use a coordinate plane to determine what happens when two more planes intersect. [2:26]
Instructional Video
Sophia Learning

Sophia: Nets

For Students 6th - 8th
Determine which two-dimensional and three-dimensional figures are created with net in this video tutorial lesson. Assess learning with a quiz. [3:27]
Instructional Video
Sophia Learning

Sophia: Perpendicular Lines

For Students 9th - 10th Standards
In this video tutorial [2:10], perpendicular lines are defined and explained in this lesson. Take a quiz to assess learning.
Instructional Video
Sophia Learning

Sophia: Proof (Harder)

For Students 9th - 10th
This geometry resource discusses two types of proof. Video lessons demonstrating a flow proof and a two-column proof are included.
Instructional Video
Sophia Learning

Sophia: Right Angles

For Students 9th - 10th
Right angles are defined in this video lesson. Take quiz to assess learning. [1:32]
Instructional Video
Sophia Learning

Sophia: Area of a Parallelogram With Triangles and Rectangles

For Students 9th - 10th Standards
In this video tutorial lesson, determine the area of a parallelogram using triangles and rectangles then assess learning with a quiz. [3:34]
Instructional Video
Massachusetts Institute of Technology

Mit: Blossoms: Are Random Triangles Acute or Obtuse?

For Teachers 9th - 10th
An MIT mathematics professor examines the probability of a random triangle being either obtuse or acute in a video [32:44] on geometrical probability. Video is accompanied by a teacher's guide, transcript, and several links on linear...
Instructional Video
Massachusetts Institute of Technology

Mit: Blossoms: The Broken Stick Experiment

For Teachers 9th - 10th
An MIT engineering professor leads teachers and students through an activity in triangle formation and probability that requires a meter stick and other basic classroom materials. This video [33:08] is accompanied by a teacher's guide,...