Maths challenge.net: Three Circles

Round and round and round we go. Given a diagram of three circles, two of which share a point with the third circle, learners identify the radius of each circle. Doing so requires setting up and solving a system of equations based on the...

Put all that algebra learning to use! Using algebraic strategies, learners solve three-variable systems. They then use the three-variable systems to write a quadratic equation given three points on the parabola.

How do 2-D properties relate in 3-D? Lead the class in a discussion on how to draw and see relationships of lines and planes in three dimensions. The ability to see these relationships is critical to the further study of volume and...

Sal uses the elimination method to simplify a system of three variables. Next, he employs the substitution method to check his solution. This resource would nicely complement any lesson on this topic.

Nothing but net! Pupils learn to use nets to create a two-dimensional representation of a three-dimensional figure. The instructor explains each section of a net of a cube and then of a rectangular prism. 

It's about to get 3-D! The video shows your class how to expand the midpoint formula to find the midpoint of a three-dimensional segment. The example shown calculates the midpoint using the x-, y-, and z-coordinates.

How many different ways can three planes intersect? The interactive provides three movable planes. Pupils manipulate the planes to determine the number of solutions possible based upon their intersections.

Time to move into the third dimension! Learn the names of the geometric solids and count faces, edges, and vertices. Then learn to recognize nets that create a given solid. 

A "three star geometry problem" requiring knowledge of how to complete geometric proofs and some prior math skills to figure the shortest distance between the opposite corners of a cuboid.

Let's move into the third dimension! Learners explore the vocabulary and notation related to three-dimensional figures. The video covers examples of pyramids, but the vocabulary is universal to all 3-D objects.