Author Archives: hangtime

What Are Similar Polygons?

This video explains the main things you need to know about similar triangles and polygons: what they are and how to spot them. It also covers types of polygons that are ALWAYS similar to each other like squares, equilateral triangles, special triangles, etc.

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Sides of Similar Polygons

This video covers a bunch of examples of the most common type of question you'll see about similar triangles and polygons: finding the lengths of missing sides (solving for x) between figures you are told are similar.

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The Golden Ratio

The Golden Ratio is a very specific ratio -- 1 to 1.618 -- that can refer to either a segment or a rectangle. This video explains what the ratio is and where it comes from, and it also shows you how to use it in word problems.

This video appears on the page: Ratios & Proportions

Properties Of Ratios

This is sort of an algebra topic, but usually where you'll need to know it is in Geometry. This video starts with basic geometry problems about similar polygons and triangles, but then it gets into honors topics such as how to compare ratios and ratio "properties".

This video appears on the page: Ratios & Proportions

What Are Ratios & Proportions?

This video introduces ratios so that you'll have the basics of what ratios are, how they are written, and what they mean. These are key basics whether you're studying similar triangles in geometry or you're about to take the SAT.

This video appears on the page: Ratios & Proportions

Ratios & Proportions
What Are Ratios & Proportions?
Properties Of Ratios
The Golden Ratio

These videos introduce the aspects of ratios and proportions that you will need whether you're in Geometry or you're about to take the SAT.

Part of the course(s): Geometry

Trapezoid Proofs

When it comes to trapezoid proofs, they're almost always about isosceles trapezoids because otherwise there's nothing trapezoid-specific about them: you'd just end up using parallel line theorems. So this video just covers isosceles trapezoids as well.

This video appears on the page: Trapezoids

Trapezoid Theorems & Problems

This video covers the theorems and problems you'll see for trapezoids. Most of them are about isosceles trapezoids because that's mostly what you'll ever see in class and on admissions tests, but the video also covers the couple of curve balls you should be on the lookout for.

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Trapezoids:
Trapezoid Theorems & Problems
Trapezoid Proofs
Areas of Trapezoids

Trapezoids are technically quadrilaterals with a single pair of parallel sides, but the reality is that most of the problems you'll ever see are isosceles trapezoids. So in this chapter most of the problems and proofs are about isosceles trapezoids, but we also discuss the little trick questions where teachers and test makers throw in the weird non-standard trapezoids to try and throw you off.

Part of the course(s): Geometry

Kite Theorems, Problems & Proofs

Kites, if you've never heard of them (because your class doesn't cover them), are kite-shaped. And if you haven't heard of them, it's probably because your class doesn't cover them, so you can skip this video. For the rest of you, sit back and relax as we check out a few obscure kite theorems.

This video appears on the page: Rectangles, Squares, Kites & Rhombuses

Rectangles & Squares

You probably think you already know everything you could ever need to know about rectangles and squares from elementary school. And you're right. But this being geometry class, they always find a way to come up with some theorems, however pointless, so that's what this video is about.

This video appears on the page: Rectangles, Squares, Kites & Rhombuses

Rhombus Theorems, Problems & Proofs

This video focuses only on rhombuses (rhombusi) because -- as you already know -- rhombuses are so cool that they deserve their own video and then some! Problems, theorems, proofs, fantastic.

This video appears on the page: Rectangles, Squares, Kites & Rhombuses

Summary of Rectangles vs Squares vs Rhombuses vs Kites

It's pretty easy to keep the major stuff straight, things like that rhombuses are parallelograms with 4 equal sides. But whose diagonals are perpendicular and whose bisect? It's all boiled down into a quick review in this short video.

This video appears on the page: Rectangles, Squares, Kites & Rhombuses

Rectangles, Squares, Kites & Rhombuses
Summary of Rectangles vs Squares vs Rhombuses vs Kites
Rhombus Theorems, Problems & Proofs
Rectangles & Squares
Kite Theorems, Problems & Proofs

These quadrilaterals are kind of like The Beatles: most people have only heard of three of them: squares, rectangles, and rhombuses (rhombusi). Kites, on the other hand, are only covered in some geometry classes. This chapter has theorems, problems and proofs for all of them, but if your class doesn't cover kites, you probably shouldn't use those theorems on your next test.

Part of the course(s): Geometry

Parallelogram Proofs

Proofs! Usually you're being asked to prove that something is a parallelogram (or parallelagram), other times you're given a parallelogram and asked to prove something about it. In this video we do both, including the proof that opposite angles of a parallelogram are congruent.

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Parallelograms in X-Y

This video covers one specific type of parallelogram (or parallagram) problem that is covered in every class. If you're in honors, you'll probably have to be able to do all of these, even the hard ones.

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Parallelogram Problems

This video shows you the most common types of problems you'll see for parallelogram (or parallelagram), and shows you how to solve them. Solving for missing angles and side lengths, solving for X, etc.

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Parallelogram Theorems

This video gives you a quick intro to the various parallelogram (or parallelagram) theorems you might need for proofs: opposite angles and sides are congruent; adjacent angles are supplementary; diagonals bisect each other... And so much more!

This video appears on the page: Parallelograms

Parallelograms
Parallelogram Theorems
Parallelogram Problems
Parallelograms in X-Y
Parallelogram Proofs

Theorems, problems, and proofs involving parallelograms.

Part of the course(s): Geometry

Distance from Points to Lines & Planes

The shortest video on the site. I could explain what it covers, but it would be faster for you to just watch the darned thing!

This video appears on the page: Triangle Inequalities & Side Lengths