Get right up and split it in half. Using a diagram, the video provides the definition of a perpendicular bisector. The portion in a playlist on basic geometry explains perpendicular bisector of a segment and of triangle sides properties.

Two sets of congruent angles leads to three. Using diagrams of two triangles, the presentation intuitively shows that if two sets of angles are congruent, the third set is too. The portion of a geometry playlist uses that information to...

Use the opposite to organize angles or sides. The video provides the relationship of angle measures based on the lengths of sides in a triangle and its converse. Using two triangles, the segment of a larger playlist on geometry shows the...

Can any three lengths make a triangle? One of the videos in a playlist on basic geometry introduces the Triangle Inequality Theorem. Using three given lengths, the presentation illustrates the restrictions on lengths of any side of a...

Find the location of altitudes—from any elevation! The video presents the definition of an altitude of a triangle. By drawing examples, the segment of a larger geometry playlist highlights the location of altitudes of various triangle...

If two sets of angles are equal, the third set is too. An informative portion of a playlist on geometry develops the Third Angle Theorem for triangles. Using the theorem, the presenter shows how to determine the measure of missing angles...

Use half the length to connect the midpoints. A section of a playlist on geometry introduces the concept of a midsegment of a triangle and how to find it. The video states the properties of the midsegment which make up the Midsegment...

SAS is not just a spy organization. A section of an extensive geometry playlist introduces a way to show two triangles are congruent, SAS. Using diagrams, the video provides an explanation by showing only one triangle is formed with two...

Use the inside to find the outside. The resource presents two theorems dealing with exterior angles of a triangle. Using the two theorems, the segment from a larger geometry playlist works problems to solve for angle measures.

The measures all add up. The presentation, part of a helpful playlist on geometry, provides the statement of the Triangle Sum Theorem. Using the theorem, the video shows how to find the missing measure of an angle.

For your eyes only: classify the names of polygons. After providing the definition of a polygon, the video introduces the two major classifications of polygons, concave and convex. The segment of a larger playlist on geometry continues...

How did polygons get their name? A brief video in the Socratica Geometry series explains the naming convention for polygons. Of course, this occurs after defining the term polygon.

Base your calculations of the areas of triangles on their bases. An illuminating video in the Socratica Geometry playlist explains how to determine the areas of a triangle. The video uses an animation to illustrate how triangles with the...

What shapes classify as a polygon? The resource provides the definition of a polygon and provides examples of polygons and shapes that are not polygons. The presentation gives an explanation of why each shape falls into the particular...

What has three sides and is adorable? A-cute triangle. The resource introduces triangles and how to classify them by sides and angles or both. The video concludes with using the sum of the angles of a triangle to show how to solve for a...

Showing is better than telling in a short demonstration video to find the area of a circle. The silent narrator transforms the circle, made from ball chain, into a triangle you can measure with a ruler, labeling quantities each...

No one wants to pay more for rent than they need to. Here is a video where future renters can learn how to fairly split rent with roommates based on room preferences. An explanation of the Sperner's lemma using an simplex isn't as...

Sing along to a simple, yet informative, music video featuring eight shapes—square, circle, triangle, rectangle, star, heart, oval, and diamond.

Show your class that finding angle measures is a regular calculation with a resource that provides 12 problems dealing with the measures of angles in regular polygons. Pupils use formulas for the sum of measures of angles in a polygon to...

Using patterns to build a formula is an important mathematical skill. Pupils discover a formula to find the sum of interior angles in a polygon by analyzing a pattern. The additional videos show how to use the formula to find various...

Get to know the triangle, circle, and square with a music video filled with hand-drawn animation set to a laid back beat. 

Need to find the length of a side of a right triangle? Just use the Pythagorean Theorem! Follow along as the tutor defines the Theorem, explains how it works, then uses it to determine the missing length of a right triangle. 

Is prism just another mathematical term for a solid? It must be since this lesson is about volume. The teacher illustrates and explains how to find the volume of a rectangular prism and also how to find the volume of a triangular prism....

A trigonometric ratio is a ratio between two sides of a right triangle. In this problem, find sin(A) in the given right triangle. Use the ratio of the opposite side over the hypotenuse.