Curated Video
Understanding Isosceles Triangle Properties
This video explains the properties of an isosceles triangle and helps viewers answer a standardized math test question about it. The teacher breaks down each answer choice and shows how to arrive at the correct answer.
Khan Academy
Area of Diagonal Generated Triangles of Rectangle Are Equal, Geometry
This lecture explores finding the area of each of the triangles created by drawing two diagonal lines through a rectangle. It provides a detailed explanation of how to use a formula to solve the given problem. Tip: Use this for test...
Khan Academy
Area of Diagonal Generated Triangles of Rectangle are Equal, Geometry
This lecture explores the area of each triangle created by drawing two diagonal lines through a rectangle. It provides a detailed explanation of how to use a formula to solve the given problem. Tip: Use this for test preparation purposes.
CK-12 Foundation
Medians: Examples
Balance the knowledge of intersecting medians. Using examples, the portion of a geometry playlist introduces the centroid. A video describes the property of the location of the triangle medians' point of concurrency.
CK-12 Foundation
Perpendicular Bisectors: Lesson
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.
CK-12 Foundation
Triangle Proportionality: Lesson
Look at proportionality from a parallel perspective. A section of an expansive geometry playlist introduces the Triangle Proportionality Theorem. Using the theorem, the video shows how to determine missing measurements in triangles.
CK-12 Foundation
Comparing Triangle Angles and Sides: Lesson
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...
CK-12 Foundation
Triangle Inequality Theorem: Lesson
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...
CK-12 Foundation
Altitudes: Examples
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...
CK-12 Foundation
Equilateral Triangles: Lesson
Take a second look at triangles that are equal all the way around. The video reminds viewers what an equilateral triangle is and points out that the three angles are the same. Using the fact that equilateral triangles are also isosceles,...
CK-12 Foundation
Proportions with Angle Bisectors: Lesson
Half at one end becomes proportional on the other. As part of a basic geometry playlist, the video introduces the Angle Bisector Theorem. The presentation uses the theorem to find missing lengths in triangles.
CK-12 Foundation
The Third Angle Theorem: Lesson
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...
CK-12 Foundation
Angle Bisectors: Lesson
Apply bisectors and distances to angles. Using the definition of an angle bisector, a portion of a geometry playlist draws a diagram showing the angle bisector. The video details properties of an angle bisector and their converses....
CK-12 Foundation
Midsegment Theorem: Lesson
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...
CK-12 Foundation
Isosceles Triangles: Lesson
Two sides give us two angles. A segment of a playlist on basic geometry revisits isosceles triangles. The presentation explains several properties and theorems related to isosceles triangles.
CK-12 Foundation
Exterior Angles Theorems: Lesson
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.
CK-12 Foundation
Triangle Sum Theorem: Lesson
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.
TED-Ed
Why Are Manhole Covers Round?
Discover the peculiar geometric property of the curve of constant width, the Reuleaux triangle, and their intriguing connection to manhole covers with yet another fascinating TED-Ed video.
Curated OER
Why Are the Angles of Equilateral Triangles Always Equal to 60¼?
Learn how to identify an equilateral triangle by evaluating its congruent sides. Once you've determined that that sides are congruent you'll be able to use the triangle sum theorem to determine the angles in an equilateral triangle. This...
Curated OER
How Do You Find Missing Angles in a Triangle With Variables?
Are you working on finding the missing angles of triangles in your class? Consider this video. An instructor uses the triangle sum theorem to create an equation that helps her find the missing angles. She explains each step and writes...
Curated OER
What is a Triangle?
Triangles, triangles, triangles. What makes a polygon a triangle? How many types of triangles are there? How do you determine what kind of triangle it is? Watch this video as the teacher explains 'tri' meaning three, making a triangle -...
Curated OER
How Do You Find Missing Angles in a Triangle With Variables?
Are you working on finding the missing angles in triangles in your class? Consider this video. An instructor uses the triangle sum theorem to create an equation that helps her find the missing angles. She explains each step and writes...
Curated OER
How Do You Find the Angles in a Triangle if You Have a Ratio of Their Measures?
Use the Triangle Sum Theorem to find the value of each of the inside angles of a triangle. This triangle problem has to do with the ratio of the angles to each other. Find the measure of each angle if the ratio is 1:3:8. Not sure how to...
Curated OER
How Do You Find a Missing Angle in a Right Triangle?
The triangle sum theorem states that the interior angles of a triangle add up to 180 degrees. So it seems logical that if there are two known values given for the interior angles of a triangle, the third value could be found using this...