CK-12 Foundation
Special Right Triangle 30-60-90: Lesson
It is special—given one length, you can find the other two. A segment of a basic geometry playlist provides the ratio of the lengths of sides of a 30-60 right triangle. The presentation shows how to use the ratio to find side lengths...
CK-12 Foundation
Special Right Triangle 45-45-90: Lesson
Square roots connect squares and right triangles. Using the Pythagorean Theorem, the video shows the relationship between the sides and hypotenuse of a 45-45 right triangle. The portion of a larger geometry playlist applies the...
CK-12 Foundation
Applications of the Pythagorean Theorem: Lesson
The Pythagorean Theorem works for something other than right triangles; show your class all it can do. Using information from the Pythagorean Theorem, the video shows how to determine whether a triangle is an acute or obtuse triangle....
CK-12 Foundation
Simplifying Radicals Review: Lesson
This work is radical! The video provides a refresher on radicals. The segment of an extensive basic geometry playlist reminds the class of the the rules for operating and simplifying expressions involving radicals.
CK-12 Foundation
Self Similarity: Lesson
Zoom in to reveal more of the same. The resource introduces the concept of self similarity. Using a simple example, the video—part of a larger playlist covering geometry concepts—illustrates the meaning of a self similarity figure.
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
Indirect Measurement: Lesson
When the tape measure will not reach, use similarity. An installment of a large playlist on geometry introduces the method of indirect measurement. Using a story of finding the distance to the sun, the video shows how to use similar...
CK-12 Foundation
Triangle AA Similarity: Lesson
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...
CK-12 Foundation
Classifying Quadrilaterals in the Coordinate Plane: Lesson
Coordinate the classification of quadrilaterals. Given the definitions of special quadrilaterals, a portion of a geometry playlist highlights ways to classify a quadrilateral. The video takes information from figures on a coordinate...
CK-12 Foundation
Kites: Lesson
Don't just go fly a kite. The resource, part of a playlist on basic geometry, introduces the kite figure and provides examples. Using the problems, the video highlights properties of kites.
CK-12 Foundation
Parallelograms: Lesson
Properties spawn from parallel sides. With the aid of diagrams, the presentation shows the different properties of parallelograms. The segment of an extensive geometry playlist lists the properties that using the parallel sides of a...
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
HL Triangle Congruence: Lesson
Use the right congruence statement. The video introduces the Hypotenuse-Leg Theorem to prove two right triangles are congruent. Part of a geometry playlist shows that it does not matter which leg to use when proving congruence.
CK-12 Foundation
ASA and AAS Triangle Congruence Lesson
The location of the side makes a difference. One of the videos in a geometry playlist introduces angle-side-angle and angle-angle-side congruence relationships. Using drawings, the video shows how these two congruence statements are...
CK-12 Foundation
SSS Triangle Congruence: Lesson
Gimme three sides, mister! The video introduces the Side-Side-Side Triangle Congruence Theorem. Using segments of different lengths, the portion of a larger playlist on geometry shows that only one triangle can be built.
CK-12 Foundation
Chords in Circles: Lesson
Strike a chord with four theorems. The segment of a playlist on geometry introduces four basic theorems about chords in a circle. Theorems include the relationships between diameters and chords, congruent chords and arcs, and congruent...
CK-12 Foundation
Trigonometry Word Problems: Lesson
Look up or down to find the answer. A segment of an extensive playlist on geometry introduces angle of depression and elevation to find indirect measurements. Using trigonometric ratios, the presentation finds missing sides and...
CK-12 Foundation
The Trigonometric Ratios: Lesson
SOH, what is this thing called trigonometric ratios? A section of an extensive playlist on geometry identifies the adjacent and opposite sides in relationship of an angle. Using the identified sides, the video defines the sine, cosine,...
CK-12 Foundation
Inscribed Similar Triangles: Lesson
Create similar triangles with a little altitude. A section of an extensive playlist on basic geometry discusses how an altitude of a right triangle creates similar triangles. Using the theorem, the presentation finds unknown side...
CK-12 Foundation
Using the Pythagorean Theorem: Lesson
Is it right to use the converse? A segment of a basic geometry playlist introduces the Pythagorean Theorem and its converse. The video uses Pythagorean triples when finding whether a triangle is a right triangle or not.
CK-12 Foundation
Dilation in the Coordinate Plane: Lesson
Multiply coordinates to either shrink or enlarge a figure. An informative segment of a geometry playlist introduces dilation on the coordinate plane. The dilations in the resource use the origin as the center of dilation, which makes...